Integrative Zoology 2014; 9: 1–13
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doi: 10.1111/1749-4877.12011
REVIEW
Annotated checklist and fisheries interactions of cetaceans in Togo, with evidence of Antarctic minke whale in the Gulf of Guinea Gabriel H. SEGNIAGBETO,1,2 Koen VAN WAEREBEEK,2,3,4 Joseph E. BOWESSIDJAOU,1 Koffivi KETOH,1 Takouda K. KPATCHA,1 Kotchikpa OKOUMASSOU5 and Kossi AHOEDO6 1
Department of Zoology and Animal Biology, University of Lomé, Lomé, Togo, 2Agbo-Zegué, Togolese Society for Nature Conservation, Lomé, Togo, 3Conservation and Research of West African Aquatic Mammals (COREWAM), c/o Department of Marine and Fisheries Sciences, University of Ghana, Legon, Ghana, 4Peruvian Centre for Cetacean Research, Lima, Peru, 5 Department of Fauna and Hunting, Ministry of Environment and Forest Resources, Lomé, Togo and 6Department of Fisheries and Aquaculture, Ministry of Agriculture, Animal Breeding and Fisheries, Lomé, Togo
Abstract Based on strandings and captures, 9 cetacean species, including 6 odontocetes and 3 mysticetes, are documented (photos and specimens) in Togo’s coastal waters (newly-recorded species marked with an asterisk): Antarctic minke whale (Balaenoptera bonaerensis*), Bryde’s whale (Balaenoptera brydei or B. edeni), humpback whale (Megaptera novaeangliae), sperm whale (Physeter macrocephalus), pygmy sperm whale (Kogia breviceps*), short-finned pilot whale (Globicephala macrorhynchus*), pantropical spotted dolphin (Stenella attenuata*), common bottlenose dolphin (Tursiops truncatus) and common dolphin Delphinus sp. An anecdotal sighting record for killer whale (Orcinus orca) is considered reliable. The lack of Sousa teuszii records in Togo is consistent with its apparent contemporaneous absence in Ghana. The B. bonaerensis specimen, entangled in a purse seine set on small pelagics, is a first record for the Gulf of Guinea. The occurrence of this Southern Ocean species north of the equator underscores the severe gaps in our understanding of cetacean distribution off western Africa. The majority of artisanal fishermen operating in Togolese coastal waters are of Ghanaian origin and are thought to promote trade and consumption of cetacean bushmeat. Because captures are illegal, enforced with some success in the main fishing centers, covert landings of cetaceans are exceedingly difficult to monitor, quantify or sample. Concern is expressed about pollution of Togo’s coastal waters with heavy metals due to phosphorite mining and export from the coastal basin near Hahotoé and Kpogamé. Key words: bycatches, capture, cetacean bushmeat, dolphin, Gulf of Guinea, stranding, whale
Correspondence: Koen Van Waerebeek, Conservation and Research of West African Aquatic Mammals (COREWAM), c/o Department of Marine and Fisheries Sciences, PO Box LG99, University of Ghana, Legon, Ghana. Email: [email protected]
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INTRODUCTION International conventions concerning fauna management and conservation commonly apply the range state concept as a crude but practical tool to summarize a taxon’s large-scale zoogeography. However, for many
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coastal nations in western Africa, the cetaceans occurring in their territorial and exclusive economic zone waters remain incompletely documented and often not even basic species checklists exist (e.g. Jefferson et al. 1997; Perrin & Van Waerebeek 2007; Uwagbae & Van Waerebeek 2010; Weir 2010). Although it may be tempting to extrapolate distributions from better-surveyed contiguous nations, these remain scientific approximations and cannot substitute national research. Literature on mammalian biodiversity in Togo is minimal (Roure 1966; Wilson & Reeder 2005; WICE 2011) and marine mammals are not covered. With no evidence of historical whaling off Togo, whales were first noticed in the 1990s. From 1996 to 2001, a small-scale sports fishing and humpback whale-watching business operated from Lomé Port (Segniagbeto & Van Waerebeek 2010). Researchers in Benin conducted exploratory surveys from 1999 to 2002 and demonstrated the Bight of Benin as a wintering and nursery ground for a Southern Hemisphere humpback whale population (Van Waerebeek et al. 2001; Van Waerebeek 2003). In 2000–2003, a first evaluation of the status of Togo’s cetaceans was conducted as part of the United Nations Environment Program/Convention of Migratory Species (UNEP/CMS) West African Cetacean Project-3 (WAFCET-3). Preliminary results were presented to the International Whaling Commission (IWC) Scientific Committee (Segniagbeto & Van Waerebeek 2010). Building on that document we here review all available information on dolphins and whales in Togo, up to 2011, and summarize the composition of Togo’s fisheries with respect to known and potential interactions with cetaceans, as an update to Maigret (1994).
MATERIALS AND METHODS Study area The Gulf of Guinea is defined as the sea bordered on the southwest by a line running in the southeastern direction from Cape Palmas (Harper), eastern Liberia, to Cape López, Gabon (International Hydrographic Organization 1953). Togo (République Togolaise), located at the northern Gulf of Guinea, consists of a narrow strip of land stretching north–south over 660 km between 06°–11°N and 00°–02°E, bordered in the west by Ghana and in the east by Benin (Fig. 1). Togo’s coastline extends east–west over 50 km of mostly sandy beaches facing the Bight of Benin. The 1500 km2 continental shelf is narrow, on average 22–24 km wide (Crosnier & Berrit 1963). A fossil barrier reef juts out from the sandy
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Figure 1 The location of Togo (triangle) in the Bight of Benin, northern Gulf of Guinea.
bottom, running almost parallel to shore, at the 52–56 m isobath and continues into Benin. Isolated reef remnants dot the outer shelf zone, up to the shelf edge, at 100 m depth. In the Gulf of Benin, sea surface temperatures (SST) normally oscillate between 25 and 29 °C but may drop to 20 °C during periods of cool upwelling. Two periods of low SST alternate with 2 periods of high SST. The first low lasts for 2.5–4 months in May– Aug as southwest monsoon winds blow, and a second low occurs in Dec–Jan due to upwelling pushed up by the northern harmattan wind, with SST minima of 21.5 °C in Jul and 23.9 °C in Jan. The warm periods in Feb– Apr/May and Aug–Dec reach SST maxima of 29 and 28.8 °C, respectively, in Apr and Nov (Cuaz 1960; Boukari 1966). The subequatorial climate has 2 rainy seasons, the main one from Mar to Jul (peaking in Jun) and a short rainy season from Sep to Nov (peaking in Oct); the dry seasons peak in Dec–Jan and in Aug (Eldin 1971).
Data sources Specimens and photographic evidence originated from strandings and bycatches in local fisheries, documented by the authors (but mainly G. H. Segniagbeto) during at least monthly coastal monitoring visits to Togo’s 16 ports and fish landing sites (Fig. 2) in the period Dec 2003–Nov 2004. The main purpose was to monitor fisheries interactions with aquatic mammals and sea turtles. Few skeletal specimens could be acquired (see subsection below on folk knowledge and anecdotal records)
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Checklist of the cetaceans of Togo
Figure 2 Coastline of Togo with the 16 fishing ports and landing sites monitored for cetacean captures and strandings.
and several specimens held by coastal residents were examined in situ. From 2005 until Dec 2010, information was gathered opportunistically during occasional visits to fisheries centers. Characteristics of Togo’s fisheries are summarized from personal observations and information obtained through the Direction des Pêches et de l’Aquaculture. Field notes of unstructured interviews with fishermen and reports of sightings were evaluated for reliability. Some sighting data was provided by a French national named Franck Barbé, skipper of a yearround sport fishing and seasonal whale-watching enterprise, who operated in Togolese waters between 1996 and 2001 (Segniagbeto & Van Waerebeek 2010).
RESULTS Togo fisheries and bycatches Fish and marine invertebrates are landed at 16 coastal sites, the most important including the Port de Pêche de Lomé, Kodjoviakopé, Ablogamé, Dévikèmé, Adissen, Agbodrafo and N’lessi (Fig. 2). Small-scale fisheries are predominant both in numbers of employed fishermen and boats. While fishing occurs year-round, a high season coincides with the Jul–Oct cool upwelling when the abundant small pelagic fishes are targeted, and a low season prevalent from Nov to Jun when SST is highest. The main artisanal fishing methods are as follows: 1. Purse seines (watsa), 600–1000 m in length, are deployed from 18 to 20 m wooden canoes equipped with 20–40 hp outboard engines. Crews vary from 15 to 20 people. A typical fishing outing lasts 24 h, with
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2 shifts allowing for non-stop fishing. Main targets consist of small pelagic species like sardines [Sardinella aurita Valenciennes, 1847 and Sardinella maderensis (Lowe, 1838)], European anchovy (Engraulis encrasicolus Linnaeus, 1758), bonga shad (Ethmalosa fimbriata Bowdich, 1825) and carangues (Caranx spp. ). 2. Line-and-hook fishermen (akpom) set out in small motorized canoes carrying ice. A crew of 6–8 fishermen typically sets out to sea for 3 days and targets dorades [blackspot seabream Pagellus bagaraveo (Brünnich, 1768) and black seabream Spondyliosoma cantharus (Linnaeus, 1758)], groupers (Epinephelus spp.), snappers or Lutjanidae [e.g. Gorean snapper Lutjanus goreensis (Valenciennes, 1830)] and other reef fish inhabiting the zone near the fossil reef barrier at 50–60 m depth. 3. Beach seines (yovodo) of 200–1000 m length are deployed all along the coast except around Lomé, aided by non-motorized canoes of 12–18 m. The seines are pulled up the beach from both ends and catch juvenile sardines, anchovies and bars (Pseudotolithus sp.), among other species. 4. At least 3 types of gillnets are used: set-nets (tonga), driftnets (awli) and wide-mesh shark gillnets (gbowlédo). Operated in coastal waters from 6 to 12 m, using partly motorized canoes, gillnets may extend several hundreds of meters in length and 2 m in depth, with stretched-mesh sizes ranging between 40 and 200 mm. Gillnets target a wide range of fish species; inshore (set) gillnets take, for example, lesser African threadfin [Galeoides decadactylus (Bloch,
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1795)], croakers (Otolithes sp.) and soles (Cynoglossus spp.), while driftnets target many large pelagic fish species, such as skipjack tuna [Katsuwonus pelamis (Linnaeus, 1758)], yellowfin tuna [Thunnus albacares (Bonnaterre, 1788)], Atlantic sailfish [Istiophorus albicans (Latreille, 1804)], blue marlin (Makaira nigricans Lacépède, 1802), swordfish (Xiphias gladius Linnaeus, 1758), wahoo [Acanthocybium solandri (Cuvier, 1832)], flying fishes (Exocoetidae) and various shark species (Selachimorpha), such as blue shark [Prionace glauca (Linnaeus, 1758)], night shark [Carcharhinus signatus (Poey, 1868)], silky shark [Carcharhinus falciformis (Müller & Henle, 1839)], kitefin shark [Dalatias licha (Bonnaterre, 1788)] and African sawtail catshark (Galeus polli Cadenat, 1959). Small pelagic schooling fishes (e.g. Sardinella, Engraulis, Caranx, E. fimbriata) are mainly targeted when migrating into Togo during upwelling periods from off Côte d’Ivoire and Ghana, where they reproduce. In a 2002 national census, of the 407 canoes (pirogues), only 45% were motorized; the others used sails. The artisanal fishery is some 70% composed of foreign fishers, mainly from Ghana (Adan, Fanti, Gan and Ahlon ethnic groups) compared to 80% Ghanaians in the 1980s (Maigret 1994). Adan, from west of the Volta Delta, comprise the majority at Lomé Port. The Ahlon, an Ewe subgroup, specialize in beach seines and driftnets. Handling and commerce is the exclusive domain of female fishmongers. Fish that is not consumed locally in fresh form is smoked, air-dried or salted. In Ghana, captured small cetaceans are habitually and openly processed for food (Ofori-Danson et al. 2003; Debrah et al. 2010), while in Togo this occurs covertly (see subsection below on exploitation and conservation measures). Smoked cetacean bushmeat is traded as far away as northern Togo, Burkina Faso, Niger and Mali. The domestic industrial fishery, limited to trawlers, gradually diminished until 1999 when a single 24 m trawler operated only periodically. Togo’s Fisheries Department encouraged a full phase-out so as to optimize the management of scarce fish resources. Fish species taken by trawlers include bigeye grunt [Brachydeuterus auritus (Valenciennes, 1832)], Dentex spp., Epinephelus spp., Sciaenidae and Lutjanidae [Lutjanus goreensis (Valenciennes, 1830)]. A small-scale sport fishery catering mostly to non-locals operates from Lomé Port, and targets gamefish like blue marlin, Atlantic sailfish, wahoo, barracuda (Sphyraena sp.) and tunas.
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Figure 3 Antarctic minke whale (Balaenoptera bonaerensis) captured in a purse seine set for small pelagic fish and landed at Lomé port. Several species-diagnostic external characters (see text) are visible. First documented record for the Northern Hemisphere.
Species accounts Balaenoptera bonaerensis Burmeister, 1867 (Antarctic minke whale) Specimen A juvenile Antarctic minke whale accidentally captured in a purse seine net, set on small pelagic fishes off Djékè (06°12.342′ N, 01°29.647′ E), landed at Lomé port on 1 Aug 1998. Body length measured 596 cm. Initially offered for sale, fisheries authorities seized it because of the protected status of cetaceans in Togo. Voucher evidence consists of 3 photographs, clearly showing the short, sharply pointed, triangular head, a single prominent median head ridge (Fig. 3), throat grooves that extend just past the flippers (not reaching the umbilicus) and the short baleen plates, some anterior ones being white (Jefferson et al. 2008). The en-
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Checklist of the cetaceans of Togo
tire ventrum, including the underside of the flippers and throat, was white. The dorsum, flanks and mandibular lips were dark grey. Two light pigment swirls extended behind the blowholes drooping towards the left flank, seen also in an individual photographed in Antarctic waters (Jefferson et al. 2008). The entire upper side of the flippers was light gray, crossed by a few irregular medium grey streaks, indicative for B. bonaerensis. Absent were the bicolored flippers with brilliant white, sharply demarcated flipper bands diagnostic for the 2 subspecies of Balaenoptera acutorostrata Lacépède, 1804; that is, common and dwarf minke whales. Dorsally, flipper at insertion is blackish to deep grey in the common minke whale and brilliant white extending onto the shoulder in dwarf minke whale (e.g. Jefferson et al. 2008), both in contrast to the light grey insertion in Djékè specimen and other Antarctic minke whales (Fig. 3). Several round crater wounds and scars can be attributed to bites of squaloid sharks Isistius sp. (Jones 1971). European anchovy [Engraulis encrasicolus (Linnaeus, 1758)] is one of the main small, pelagic fishes in the western Gulf of Guinea (Koranteng 1995) and upwellinglinked seasonal catches in Togo peak precisely around Aug when the whale was entangled. Minke whales are well-known to feed in association with purse seiners setting on anchovies or sardines, and, thus, risk entanglement (e.g. Guerra et al. 1987; Martín 1996; Van Waerebeek et al. 1999). Balaenoptera brydei Olsen, 1913 (Bryde’s whale) or Balaenoptera edeni Anderson, 1878 (Eden’s whale) The taxonomic relationship between B. brydei and the diminutive B. edeni from the Indo-Pacific remains unresolved. Some (including the authors) recognize these as 2 distinct species, with B. edeni absent from the Atlantic Ocean; however, Kato and Perrin (2009) promote the view to recognize only B. edeni pending further research. Specimens Specimen TG006 (Fig. 4), comprising the left mandible, occipital–squamosal bones and baleen plates, was examined on 13 Nov 2002 at Baguida beach (06°09.57′N, 01°19.668′E), where the whale reportedly stranded some 5 years earlier (in 1997). The strongly curved mandibular ramus, which is markedly wide and massive, almost rounded in cross section, and has a prominent coronoid process, is distinctive for B. brydei (Lönnberg 1931; Omura 1959; Omura et al. 1981). It is distinguishable from a significantly less-curved ramus mandibularis, compressed in cross section and with a smaller coronoid process in the sei whale [Balaenoptera
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Figure 4 Massive left ramus mandibularis and blackish baleen plates with coarse bristles of a Bryde’s whale (Balaenoptera brydei) (TG006) stranded at Baguida beach. First documented record for Togo.
borealis Lesson, 1828 (Miller 1924)]. The broad, blackish baleen plates of TG006 have coarse, cream-grey bristles (Fig. 4) also identifiable with B. brydei (Omura 1962) and distinct from the extremely fine, white bristles in B. borealis. The partial neurocranium, mainly the occipital–squamosal bones, although too damaged to be positively diagnostic, was morphologically consistent with B. brydei. A physically mature lumbar vertebra (TG004), reportedly found in a fishing net, was examined (but not collected) by G. H. Segniagbeto and K. Van Waerebeek at Kotokoukondji on 13 Nov 2002. Size and morphology agreed with Bryde’s whale, particularly the strongly caudally-inclined (52° from perpendicular) processus spinosus (Lönnberg 1931; Omura et al. 1981), differing
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Figure 5 A neonate humpback whale (Megaptera novaeangliae) stranded at Lomé on 22 Aug 2005 following an indeterminate fisheries interaction.
Figure 6 Occipital view of the weathered (inverted) calvaria of a sperm whale (Physeter macrocephalus) of unknown sex, photographed on Adissen beach in 2002, but reported stranded circa 1992. First documented record for Togo.
from the nearly vertical processus spinosi in B. borealis (see Miller 1924; Perrin et al. 1996) and moderately inclined processus in other large balaenopterids. We tentatively assign TG004 to B. brydei. No sightings of Bryde’s whales have been reported. Megaptera novaeangliae (Borowski, 1781) (humpback whale) Specimens Three individuals are documented. A humpback whale that stranded on the beach of Baguida (06°09.570′N, 01°19.668′E) on 28 Oct 2002 was
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cut up for local consumption (marine bushmeat). Some of its oil was harvested for use as traditional medicine. A dried skin sample is archived (K281002). A neonate, either moribund or freshly dead (Fig. 5), stranded at Ablogamé, Lomé (06°7.735′N, 01°15.735′E) on 22 Aug 2005 (Tchibozo & Van Waerebeek 2007). Two clear rope-burn marks on its tail stock, inflicted either peri-mortem or post-mortem, suggest a fisheries interaction. The animal’s white throat is consistent with coloration patterns typically found in Southern Hemisphere populations (Jefferson et al. 2008). A second neonate washed ashore in advanced decomposition at Kpogan (06°10.37′N, 01°22.95′E) in Oct 2009 and was positively identified mainly from its elongated flippers (photo in authors’ archives). Incidental sightings G. H. Segniagbeto observed 2 humpback whales near the beach at Agbodrafo (06°12.00′N, 01°28.73′E) on 6 Oct 2002. On 15 Nov 2002, G. H. Segniagbeto and K. Van Waerebeek were shown a video by Gilles Guido of the French Embassy at Lomé documenting 2 groups of, respectively, 5–6 and 2 humpback whales filmed during a small-boat outing off Lomé on 20 Oct 2002. Jan Vlaar (pers. comm., 1 Nov 2000) reported three sightings off western Togo: 2 adults on 1 Nov 1999, an adult/calf pair on 24 Sep 2000 and a group of 6 adults engaging in energetic surfaceactive behavior, supported by photos (Van Waerebeek et al. 2001). The video Togo le Paradis des Baleines, produced by Emile Tissot and Télévision Togolaise, features a boat-based encounter with several humpback whales off Lomé, the city recognizable in the background (Segniagbeto & Van Waerebeek 2010). The recording has been commercially available in Lomé since 1998. Original cassettes and a digitized copy are archived at Agbo-Zegue, Lomé and at the CEPEC office, Lima. Supported records and verbal reports from whalewatchers, artisanal fisheries and year-round sports fishing efforts concur and suggest a seasonal presence of humpback whales in Togo’s shelf waters from mid-Aug to early Dec, which coincides with Benin and Ghana records (Van Waerebeek et al. 2001, 2009; Tchibozo & Van Waerebeek 2007; Segniagbeto & Van Waerebeek 2010). Weir (2010) describes Togo as range state based exclusively on the aforementioned, original sources. Physeter macrocephalus Linnaeus, 1758 (sperm whale) Specimens Two specimens are known from Togo. We examined the weathered calvaria of a mid-sized sperm whale (TG003; approximate condylobasal length, 249 cm) at Adissen beach (06°11.733′N, 01°27.210′E) on 12 Nov 2002 (Fig. 6). Residents indicated the whale of un-
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known sex had stranded approximately 10 years earlier. Re-examined on 29 Apr 2010, the calvaria had dramatically weathered, reduced to occipital bone and condyli. Skeletal remains of a second sperm whale (TG011), a physically immature animal of unknown sex, consisted of the left mandible, 1 tooth, 1 rib and a few caudal vertebrae. G. H. Segniagbeto and K. Van Waerebeek examined TG011 remains at a compound occupied by fishermen from Agbodrafo and nearby Kpeme (06°12.373′N, 01°29.865′E) on 29 Apr 2010. Reportedly, the sperm whale stranded in Mar 2010. Kogia breviceps (de Blainville, 1838) (pygmy sperm whale) Specimen A 285 cm pygmy sperm whale landed at Agblogamé, near Lomé, on 23 Mar 2012 (Fig. 7). Sex was not recorded but the size suggests it was an adult. The freshly-dead specimen (condition code 3) had probably been captured in a drift gillnet by local, small-scale fishermen and was retained to be used for human consumption. This is the first authenticated record of pygmy sperm whale for the Gulf of Guinea. One dwarf sperm whale [Kogia sima (Owen, 1866)] and 2 Kogia sp. have been reported from Ghana, all bycatches (Van Waerebeek et al. 2009). No Kogia sightings exist for the Gulf of Guinea. Globicephala macrorhynchus Gray, 1846 (short-finned pilot whale) The short-finned pilot whale is the fifth most commonly landed cetacean in Ghanaian ports (Ofori-Danson et al. 2003; Van Waerebeek et al. 2009; Debrah et al. 2010), and is sighted in the Gulf of Guinea (reviewed in Weir 2010). Specimen A 355 cm female short-finned pilot whale was found alive, with slight external bleeding, on a beach near the main jetty of Lomé port, on 28 Sep 2010 (Fig. 8). As a severed rope was tied around the tailstock, an abandoned bycatch was suspected. The animal was refloated and towed out to sea for release by a small Navy tugboat, but it is unclear whether it survived. The short-finned pilot whale (Globicephala macrorhynchus Gray, 1846) is the only Globicephala sp. known in the Gulf of Guinea (Perrin & Van Waerebeek 2007; Weir 2010). Stenella attenuata (Gray, 1846) (pantropical spotted dolphin) Specimen The adult skull of a Stenella attenuata (Fig. 9) captured off Togo’s coast, reportedly by Ghanaian fishermen, was obtained by G. H. Segniagbeto at Gbet-
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Figure 7 An adult-sized pygmy sperm whale (Kogia breviceps) landed at Agblogamé in Mar 2012. The small, falcate dorsal fin, positioned behind midback (shown here) together with the beakless head, conical in dorsal profile and small body size are diagnostic.
Figure 8 A juvenile female short-finned pilot whale (Globicephala macrorhynchus) found alive on a beach near the port of Lomé on 28 Sep 2010. A suspected abandoned catch, the animal was later released. First documented record for Togo.
Figure 9 Cranially adult skull (TG008) of a pantropical spotted dolphin (Stenella attenuata) captured by fishermen from Gbetsogbe. First documented record for Togo.
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sogbé (06°09.145′N, 01°18.383′E) on 2 Jul 2003. The referred specimen is TG008 in the Agbo-Zegue biological collection. Tooth counts are: UR 41, UL 41, LR 40, LL 40. In Ghana S. attenuata accounts for 13.2% of cetacean landings, the second most commonly captured species. Atlantic spotted dolphin Stenella frontalis (G. Cuvier, 1829) seems rare, comprising only 0.5% of cetacean landings (Van Waerebeek et al. 2009; Debrah et al. 2010). Sightings No supported sightings exist for Togo. Ten fishermen from Lomé, Gbetsogbe, Agbodrafo and Aneho, who had attended an introductory course in species identification and made notes while out fishing in 2003– 2004, reported 19% of dolphin groups sighted as ‘spotted dolphins’; we surmise that most of these were probably S. attenuata. Tursiops truncatus (Montagu, 1821) (common bottlenose dolphin) Specimen An adult-sized common bottlenose dolphin stranded (code 3) on a beach near Lomé at 06°07.80′N, 01°14.942′E on 13 Sep 2010, as reported by Commandant de Brigade Issifou Minkaïl Yamoussa (Fig. 10). The cause of death is unknown. K. Okoumassou buried the carcass aiming to retrieve the skeleton later. Leftside tooth counts were UL 19 and LL 19. This is the first specimen record of T. truncatus in Togo. No documented sightings are known. T. truncatus is the third (12.3%) most commonly captured cetacean in Ghana (Debrah et al. 2010). A small group was seen foraging around encircling gillnets set near shore just west of Cotonou, Benin (Van Waerebeek et al. 2009). Delphinus sp. (common dolphin) Specimen On 13 Nov 2003, G. H. Segniagbeto and K. Van Waerebeek examined the beach-worn calvaria of an adult common dolphin (TG005) conserved by a resident from Kotokoukondji. The minumum count (eroded tip) of maxillar alveoli was 41 each side. Deep palatal grooves were diagnostic for the genus Delphinus; however, bone erosion and the lack of cranial measurements impeded species-level identification. The calvaria could not be collected but a low-resolution photo (ventral aspect) is archived. In Ghana, 9.4% (n = 212) of landed cetaceans are long-beaked common dolphins Delphinus capensis Gray, 1828 (Van Waerebeek et al. 2009). Orcinus orca (Linnaeus, 1758) (killer whale) Skipper Barbé described his sighting of a pod of 4 killer whales, including an adult male, a female with calf and a female/immature in Togo’s shelf waters on
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30 Jun 1998. Barbé added having encountered the species a number of times between 1996 and 2001. Several fishermen independently described ‘des orques’ predating on humpback whales. Hammond and Lockyer (1988) listed 3 killer whale sightings from Ghana in Aug 1972. Although unauthenticated, these reports are considered credible given O. orca practically cannot be mistaken. The only supported case from the northern Gulf of Guinea is an adult skull of unspecified origin within Ghana curated at the University of Ghana and examined by Van Waerebeek et al. (2009). Unidentified cetaceans 1. In 1974, a large whale stranded on the beach in front of l’Hôtel de la Paix at Lomé (A. Kokou, pers. comm.). Another whale live-stranded near Lomé Rivages, a few kilometers southwest of Lomé, in Oct 1999. Personnel from the Direction de l’Elevage et de la Pêche refloated the latter. 2. A small, yellowish-gray baleen plate (80 × 32 mm), unfortunately without bristles, was obtained at Lomé’s Marché des Fétishes, Akodésséwa, in Sep 2008. A baleen plate length: breadth quotient of 2.5 seems too broad for minke whale and for now it remains incertae sedis.
Folk knowledge and anecdotal records The Ewe people, indigenous of coastal Togo and eastern Ghana, venerate aquatic mammals and sea turtles, a cultural trait linked to traditional animistic beliefs including voodoo, and typically release accidentally caught animals if alive. In addition, as in Vietnam (Smith et al. 1997), bones of stranded cetaceans are respectfully conserved in shrines, often simple open-air enclosures (Ofori-Danson et al. 2003; Van Waerebeek et al. 2009). Albeit conservation-friendly, this tradition hampered research as the obtention of permission to examine skeletal remains required lengthy negotiations if not incentives, while the acquisition or even photographing of specimens was often prohibitive. Many artisanal fishers interviewed showed a familiarity with the seasonal inshore presence of humpback whales and their calves. Shore-based sightings were described at Adissen (06°11.733′N, 01°27.21′E), N’lessi (06°13.445′N, 01°35.633′E) and Payemé (06°14.417′N, 01°37.628′E). Fishers reported different species of dolphins (gagadolo, giga, atui and takpe) foraging year-round in coastal waters, while some complained of depredation of netted fish. Sport fishing and whale-watching outings off Lomé in 1996–2001 also indicated year-round sightings of common dolphins, bottlenose dolphins and (unspecified)
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Figure 10 An adult-sized common bottlenose dolphin (Tursiops truncatus) stranded in early decomposition on a beach near Lomé on 13 Sep 2010. First documented record for Togo.
spotted dolphins Segniagbeto & Van Waerebeek 2010). Barbé further reported groups of 10–40 pilot whales in continental slope waters during periods of high SST (>28 °C), from mid-Feb to the first week of Jun, and a pod of 3 sperm whales approximately 20 nautical miles south of Lomé on 13 Jun 1997. Fishermen from N’lessi who had received basic training reported 42 cetacean sightings in water
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doi: 10.1111/1749-4877.12011
REVIEW
Annotated checklist and fisheries interactions of cetaceans in Togo, with evidence of Antarctic minke whale in the Gulf of Guinea Gabriel H. SEGNIAGBETO,1,2 Koen VAN WAEREBEEK,2,3,4 Joseph E. BOWESSIDJAOU,1 Koffivi KETOH,1 Takouda K. KPATCHA,1 Kotchikpa OKOUMASSOU5 and Kossi AHOEDO6 1
Department of Zoology and Animal Biology, University of Lomé, Lomé, Togo, 2Agbo-Zegué, Togolese Society for Nature Conservation, Lomé, Togo, 3Conservation and Research of West African Aquatic Mammals (COREWAM), c/o Department of Marine and Fisheries Sciences, University of Ghana, Legon, Ghana, 4Peruvian Centre for Cetacean Research, Lima, Peru, 5 Department of Fauna and Hunting, Ministry of Environment and Forest Resources, Lomé, Togo and 6Department of Fisheries and Aquaculture, Ministry of Agriculture, Animal Breeding and Fisheries, Lomé, Togo
Abstract Based on strandings and captures, 9 cetacean species, including 6 odontocetes and 3 mysticetes, are documented (photos and specimens) in Togo’s coastal waters (newly-recorded species marked with an asterisk): Antarctic minke whale (Balaenoptera bonaerensis*), Bryde’s whale (Balaenoptera brydei or B. edeni), humpback whale (Megaptera novaeangliae), sperm whale (Physeter macrocephalus), pygmy sperm whale (Kogia breviceps*), short-finned pilot whale (Globicephala macrorhynchus*), pantropical spotted dolphin (Stenella attenuata*), common bottlenose dolphin (Tursiops truncatus) and common dolphin Delphinus sp. An anecdotal sighting record for killer whale (Orcinus orca) is considered reliable. The lack of Sousa teuszii records in Togo is consistent with its apparent contemporaneous absence in Ghana. The B. bonaerensis specimen, entangled in a purse seine set on small pelagics, is a first record for the Gulf of Guinea. The occurrence of this Southern Ocean species north of the equator underscores the severe gaps in our understanding of cetacean distribution off western Africa. The majority of artisanal fishermen operating in Togolese coastal waters are of Ghanaian origin and are thought to promote trade and consumption of cetacean bushmeat. Because captures are illegal, enforced with some success in the main fishing centers, covert landings of cetaceans are exceedingly difficult to monitor, quantify or sample. Concern is expressed about pollution of Togo’s coastal waters with heavy metals due to phosphorite mining and export from the coastal basin near Hahotoé and Kpogamé. Key words: bycatches, capture, cetacean bushmeat, dolphin, Gulf of Guinea, stranding, whale
Correspondence: Koen Van Waerebeek, Conservation and Research of West African Aquatic Mammals (COREWAM), c/o Department of Marine and Fisheries Sciences, PO Box LG99, University of Ghana, Legon, Ghana. Email: [email protected]
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INTRODUCTION International conventions concerning fauna management and conservation commonly apply the range state concept as a crude but practical tool to summarize a taxon’s large-scale zoogeography. However, for many
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coastal nations in western Africa, the cetaceans occurring in their territorial and exclusive economic zone waters remain incompletely documented and often not even basic species checklists exist (e.g. Jefferson et al. 1997; Perrin & Van Waerebeek 2007; Uwagbae & Van Waerebeek 2010; Weir 2010). Although it may be tempting to extrapolate distributions from better-surveyed contiguous nations, these remain scientific approximations and cannot substitute national research. Literature on mammalian biodiversity in Togo is minimal (Roure 1966; Wilson & Reeder 2005; WICE 2011) and marine mammals are not covered. With no evidence of historical whaling off Togo, whales were first noticed in the 1990s. From 1996 to 2001, a small-scale sports fishing and humpback whale-watching business operated from Lomé Port (Segniagbeto & Van Waerebeek 2010). Researchers in Benin conducted exploratory surveys from 1999 to 2002 and demonstrated the Bight of Benin as a wintering and nursery ground for a Southern Hemisphere humpback whale population (Van Waerebeek et al. 2001; Van Waerebeek 2003). In 2000–2003, a first evaluation of the status of Togo’s cetaceans was conducted as part of the United Nations Environment Program/Convention of Migratory Species (UNEP/CMS) West African Cetacean Project-3 (WAFCET-3). Preliminary results were presented to the International Whaling Commission (IWC) Scientific Committee (Segniagbeto & Van Waerebeek 2010). Building on that document we here review all available information on dolphins and whales in Togo, up to 2011, and summarize the composition of Togo’s fisheries with respect to known and potential interactions with cetaceans, as an update to Maigret (1994).
MATERIALS AND METHODS Study area The Gulf of Guinea is defined as the sea bordered on the southwest by a line running in the southeastern direction from Cape Palmas (Harper), eastern Liberia, to Cape López, Gabon (International Hydrographic Organization 1953). Togo (République Togolaise), located at the northern Gulf of Guinea, consists of a narrow strip of land stretching north–south over 660 km between 06°–11°N and 00°–02°E, bordered in the west by Ghana and in the east by Benin (Fig. 1). Togo’s coastline extends east–west over 50 km of mostly sandy beaches facing the Bight of Benin. The 1500 km2 continental shelf is narrow, on average 22–24 km wide (Crosnier & Berrit 1963). A fossil barrier reef juts out from the sandy
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Figure 1 The location of Togo (triangle) in the Bight of Benin, northern Gulf of Guinea.
bottom, running almost parallel to shore, at the 52–56 m isobath and continues into Benin. Isolated reef remnants dot the outer shelf zone, up to the shelf edge, at 100 m depth. In the Gulf of Benin, sea surface temperatures (SST) normally oscillate between 25 and 29 °C but may drop to 20 °C during periods of cool upwelling. Two periods of low SST alternate with 2 periods of high SST. The first low lasts for 2.5–4 months in May– Aug as southwest monsoon winds blow, and a second low occurs in Dec–Jan due to upwelling pushed up by the northern harmattan wind, with SST minima of 21.5 °C in Jul and 23.9 °C in Jan. The warm periods in Feb– Apr/May and Aug–Dec reach SST maxima of 29 and 28.8 °C, respectively, in Apr and Nov (Cuaz 1960; Boukari 1966). The subequatorial climate has 2 rainy seasons, the main one from Mar to Jul (peaking in Jun) and a short rainy season from Sep to Nov (peaking in Oct); the dry seasons peak in Dec–Jan and in Aug (Eldin 1971).
Data sources Specimens and photographic evidence originated from strandings and bycatches in local fisheries, documented by the authors (but mainly G. H. Segniagbeto) during at least monthly coastal monitoring visits to Togo’s 16 ports and fish landing sites (Fig. 2) in the period Dec 2003–Nov 2004. The main purpose was to monitor fisheries interactions with aquatic mammals and sea turtles. Few skeletal specimens could be acquired (see subsection below on folk knowledge and anecdotal records)
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Figure 2 Coastline of Togo with the 16 fishing ports and landing sites monitored for cetacean captures and strandings.
and several specimens held by coastal residents were examined in situ. From 2005 until Dec 2010, information was gathered opportunistically during occasional visits to fisheries centers. Characteristics of Togo’s fisheries are summarized from personal observations and information obtained through the Direction des Pêches et de l’Aquaculture. Field notes of unstructured interviews with fishermen and reports of sightings were evaluated for reliability. Some sighting data was provided by a French national named Franck Barbé, skipper of a yearround sport fishing and seasonal whale-watching enterprise, who operated in Togolese waters between 1996 and 2001 (Segniagbeto & Van Waerebeek 2010).
RESULTS Togo fisheries and bycatches Fish and marine invertebrates are landed at 16 coastal sites, the most important including the Port de Pêche de Lomé, Kodjoviakopé, Ablogamé, Dévikèmé, Adissen, Agbodrafo and N’lessi (Fig. 2). Small-scale fisheries are predominant both in numbers of employed fishermen and boats. While fishing occurs year-round, a high season coincides with the Jul–Oct cool upwelling when the abundant small pelagic fishes are targeted, and a low season prevalent from Nov to Jun when SST is highest. The main artisanal fishing methods are as follows: 1. Purse seines (watsa), 600–1000 m in length, are deployed from 18 to 20 m wooden canoes equipped with 20–40 hp outboard engines. Crews vary from 15 to 20 people. A typical fishing outing lasts 24 h, with
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2 shifts allowing for non-stop fishing. Main targets consist of small pelagic species like sardines [Sardinella aurita Valenciennes, 1847 and Sardinella maderensis (Lowe, 1838)], European anchovy (Engraulis encrasicolus Linnaeus, 1758), bonga shad (Ethmalosa fimbriata Bowdich, 1825) and carangues (Caranx spp. ). 2. Line-and-hook fishermen (akpom) set out in small motorized canoes carrying ice. A crew of 6–8 fishermen typically sets out to sea for 3 days and targets dorades [blackspot seabream Pagellus bagaraveo (Brünnich, 1768) and black seabream Spondyliosoma cantharus (Linnaeus, 1758)], groupers (Epinephelus spp.), snappers or Lutjanidae [e.g. Gorean snapper Lutjanus goreensis (Valenciennes, 1830)] and other reef fish inhabiting the zone near the fossil reef barrier at 50–60 m depth. 3. Beach seines (yovodo) of 200–1000 m length are deployed all along the coast except around Lomé, aided by non-motorized canoes of 12–18 m. The seines are pulled up the beach from both ends and catch juvenile sardines, anchovies and bars (Pseudotolithus sp.), among other species. 4. At least 3 types of gillnets are used: set-nets (tonga), driftnets (awli) and wide-mesh shark gillnets (gbowlédo). Operated in coastal waters from 6 to 12 m, using partly motorized canoes, gillnets may extend several hundreds of meters in length and 2 m in depth, with stretched-mesh sizes ranging between 40 and 200 mm. Gillnets target a wide range of fish species; inshore (set) gillnets take, for example, lesser African threadfin [Galeoides decadactylus (Bloch,
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1795)], croakers (Otolithes sp.) and soles (Cynoglossus spp.), while driftnets target many large pelagic fish species, such as skipjack tuna [Katsuwonus pelamis (Linnaeus, 1758)], yellowfin tuna [Thunnus albacares (Bonnaterre, 1788)], Atlantic sailfish [Istiophorus albicans (Latreille, 1804)], blue marlin (Makaira nigricans Lacépède, 1802), swordfish (Xiphias gladius Linnaeus, 1758), wahoo [Acanthocybium solandri (Cuvier, 1832)], flying fishes (Exocoetidae) and various shark species (Selachimorpha), such as blue shark [Prionace glauca (Linnaeus, 1758)], night shark [Carcharhinus signatus (Poey, 1868)], silky shark [Carcharhinus falciformis (Müller & Henle, 1839)], kitefin shark [Dalatias licha (Bonnaterre, 1788)] and African sawtail catshark (Galeus polli Cadenat, 1959). Small pelagic schooling fishes (e.g. Sardinella, Engraulis, Caranx, E. fimbriata) are mainly targeted when migrating into Togo during upwelling periods from off Côte d’Ivoire and Ghana, where they reproduce. In a 2002 national census, of the 407 canoes (pirogues), only 45% were motorized; the others used sails. The artisanal fishery is some 70% composed of foreign fishers, mainly from Ghana (Adan, Fanti, Gan and Ahlon ethnic groups) compared to 80% Ghanaians in the 1980s (Maigret 1994). Adan, from west of the Volta Delta, comprise the majority at Lomé Port. The Ahlon, an Ewe subgroup, specialize in beach seines and driftnets. Handling and commerce is the exclusive domain of female fishmongers. Fish that is not consumed locally in fresh form is smoked, air-dried or salted. In Ghana, captured small cetaceans are habitually and openly processed for food (Ofori-Danson et al. 2003; Debrah et al. 2010), while in Togo this occurs covertly (see subsection below on exploitation and conservation measures). Smoked cetacean bushmeat is traded as far away as northern Togo, Burkina Faso, Niger and Mali. The domestic industrial fishery, limited to trawlers, gradually diminished until 1999 when a single 24 m trawler operated only periodically. Togo’s Fisheries Department encouraged a full phase-out so as to optimize the management of scarce fish resources. Fish species taken by trawlers include bigeye grunt [Brachydeuterus auritus (Valenciennes, 1832)], Dentex spp., Epinephelus spp., Sciaenidae and Lutjanidae [Lutjanus goreensis (Valenciennes, 1830)]. A small-scale sport fishery catering mostly to non-locals operates from Lomé Port, and targets gamefish like blue marlin, Atlantic sailfish, wahoo, barracuda (Sphyraena sp.) and tunas.
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Figure 3 Antarctic minke whale (Balaenoptera bonaerensis) captured in a purse seine set for small pelagic fish and landed at Lomé port. Several species-diagnostic external characters (see text) are visible. First documented record for the Northern Hemisphere.
Species accounts Balaenoptera bonaerensis Burmeister, 1867 (Antarctic minke whale) Specimen A juvenile Antarctic minke whale accidentally captured in a purse seine net, set on small pelagic fishes off Djékè (06°12.342′ N, 01°29.647′ E), landed at Lomé port on 1 Aug 1998. Body length measured 596 cm. Initially offered for sale, fisheries authorities seized it because of the protected status of cetaceans in Togo. Voucher evidence consists of 3 photographs, clearly showing the short, sharply pointed, triangular head, a single prominent median head ridge (Fig. 3), throat grooves that extend just past the flippers (not reaching the umbilicus) and the short baleen plates, some anterior ones being white (Jefferson et al. 2008). The en-
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tire ventrum, including the underside of the flippers and throat, was white. The dorsum, flanks and mandibular lips were dark grey. Two light pigment swirls extended behind the blowholes drooping towards the left flank, seen also in an individual photographed in Antarctic waters (Jefferson et al. 2008). The entire upper side of the flippers was light gray, crossed by a few irregular medium grey streaks, indicative for B. bonaerensis. Absent were the bicolored flippers with brilliant white, sharply demarcated flipper bands diagnostic for the 2 subspecies of Balaenoptera acutorostrata Lacépède, 1804; that is, common and dwarf minke whales. Dorsally, flipper at insertion is blackish to deep grey in the common minke whale and brilliant white extending onto the shoulder in dwarf minke whale (e.g. Jefferson et al. 2008), both in contrast to the light grey insertion in Djékè specimen and other Antarctic minke whales (Fig. 3). Several round crater wounds and scars can be attributed to bites of squaloid sharks Isistius sp. (Jones 1971). European anchovy [Engraulis encrasicolus (Linnaeus, 1758)] is one of the main small, pelagic fishes in the western Gulf of Guinea (Koranteng 1995) and upwellinglinked seasonal catches in Togo peak precisely around Aug when the whale was entangled. Minke whales are well-known to feed in association with purse seiners setting on anchovies or sardines, and, thus, risk entanglement (e.g. Guerra et al. 1987; Martín 1996; Van Waerebeek et al. 1999). Balaenoptera brydei Olsen, 1913 (Bryde’s whale) or Balaenoptera edeni Anderson, 1878 (Eden’s whale) The taxonomic relationship between B. brydei and the diminutive B. edeni from the Indo-Pacific remains unresolved. Some (including the authors) recognize these as 2 distinct species, with B. edeni absent from the Atlantic Ocean; however, Kato and Perrin (2009) promote the view to recognize only B. edeni pending further research. Specimens Specimen TG006 (Fig. 4), comprising the left mandible, occipital–squamosal bones and baleen plates, was examined on 13 Nov 2002 at Baguida beach (06°09.57′N, 01°19.668′E), where the whale reportedly stranded some 5 years earlier (in 1997). The strongly curved mandibular ramus, which is markedly wide and massive, almost rounded in cross section, and has a prominent coronoid process, is distinctive for B. brydei (Lönnberg 1931; Omura 1959; Omura et al. 1981). It is distinguishable from a significantly less-curved ramus mandibularis, compressed in cross section and with a smaller coronoid process in the sei whale [Balaenoptera
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Figure 4 Massive left ramus mandibularis and blackish baleen plates with coarse bristles of a Bryde’s whale (Balaenoptera brydei) (TG006) stranded at Baguida beach. First documented record for Togo.
borealis Lesson, 1828 (Miller 1924)]. The broad, blackish baleen plates of TG006 have coarse, cream-grey bristles (Fig. 4) also identifiable with B. brydei (Omura 1962) and distinct from the extremely fine, white bristles in B. borealis. The partial neurocranium, mainly the occipital–squamosal bones, although too damaged to be positively diagnostic, was morphologically consistent with B. brydei. A physically mature lumbar vertebra (TG004), reportedly found in a fishing net, was examined (but not collected) by G. H. Segniagbeto and K. Van Waerebeek at Kotokoukondji on 13 Nov 2002. Size and morphology agreed with Bryde’s whale, particularly the strongly caudally-inclined (52° from perpendicular) processus spinosus (Lönnberg 1931; Omura et al. 1981), differing
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Figure 5 A neonate humpback whale (Megaptera novaeangliae) stranded at Lomé on 22 Aug 2005 following an indeterminate fisheries interaction.
Figure 6 Occipital view of the weathered (inverted) calvaria of a sperm whale (Physeter macrocephalus) of unknown sex, photographed on Adissen beach in 2002, but reported stranded circa 1992. First documented record for Togo.
from the nearly vertical processus spinosi in B. borealis (see Miller 1924; Perrin et al. 1996) and moderately inclined processus in other large balaenopterids. We tentatively assign TG004 to B. brydei. No sightings of Bryde’s whales have been reported. Megaptera novaeangliae (Borowski, 1781) (humpback whale) Specimens Three individuals are documented. A humpback whale that stranded on the beach of Baguida (06°09.570′N, 01°19.668′E) on 28 Oct 2002 was
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cut up for local consumption (marine bushmeat). Some of its oil was harvested for use as traditional medicine. A dried skin sample is archived (K281002). A neonate, either moribund or freshly dead (Fig. 5), stranded at Ablogamé, Lomé (06°7.735′N, 01°15.735′E) on 22 Aug 2005 (Tchibozo & Van Waerebeek 2007). Two clear rope-burn marks on its tail stock, inflicted either peri-mortem or post-mortem, suggest a fisheries interaction. The animal’s white throat is consistent with coloration patterns typically found in Southern Hemisphere populations (Jefferson et al. 2008). A second neonate washed ashore in advanced decomposition at Kpogan (06°10.37′N, 01°22.95′E) in Oct 2009 and was positively identified mainly from its elongated flippers (photo in authors’ archives). Incidental sightings G. H. Segniagbeto observed 2 humpback whales near the beach at Agbodrafo (06°12.00′N, 01°28.73′E) on 6 Oct 2002. On 15 Nov 2002, G. H. Segniagbeto and K. Van Waerebeek were shown a video by Gilles Guido of the French Embassy at Lomé documenting 2 groups of, respectively, 5–6 and 2 humpback whales filmed during a small-boat outing off Lomé on 20 Oct 2002. Jan Vlaar (pers. comm., 1 Nov 2000) reported three sightings off western Togo: 2 adults on 1 Nov 1999, an adult/calf pair on 24 Sep 2000 and a group of 6 adults engaging in energetic surfaceactive behavior, supported by photos (Van Waerebeek et al. 2001). The video Togo le Paradis des Baleines, produced by Emile Tissot and Télévision Togolaise, features a boat-based encounter with several humpback whales off Lomé, the city recognizable in the background (Segniagbeto & Van Waerebeek 2010). The recording has been commercially available in Lomé since 1998. Original cassettes and a digitized copy are archived at Agbo-Zegue, Lomé and at the CEPEC office, Lima. Supported records and verbal reports from whalewatchers, artisanal fisheries and year-round sports fishing efforts concur and suggest a seasonal presence of humpback whales in Togo’s shelf waters from mid-Aug to early Dec, which coincides with Benin and Ghana records (Van Waerebeek et al. 2001, 2009; Tchibozo & Van Waerebeek 2007; Segniagbeto & Van Waerebeek 2010). Weir (2010) describes Togo as range state based exclusively on the aforementioned, original sources. Physeter macrocephalus Linnaeus, 1758 (sperm whale) Specimens Two specimens are known from Togo. We examined the weathered calvaria of a mid-sized sperm whale (TG003; approximate condylobasal length, 249 cm) at Adissen beach (06°11.733′N, 01°27.210′E) on 12 Nov 2002 (Fig. 6). Residents indicated the whale of un-
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known sex had stranded approximately 10 years earlier. Re-examined on 29 Apr 2010, the calvaria had dramatically weathered, reduced to occipital bone and condyli. Skeletal remains of a second sperm whale (TG011), a physically immature animal of unknown sex, consisted of the left mandible, 1 tooth, 1 rib and a few caudal vertebrae. G. H. Segniagbeto and K. Van Waerebeek examined TG011 remains at a compound occupied by fishermen from Agbodrafo and nearby Kpeme (06°12.373′N, 01°29.865′E) on 29 Apr 2010. Reportedly, the sperm whale stranded in Mar 2010. Kogia breviceps (de Blainville, 1838) (pygmy sperm whale) Specimen A 285 cm pygmy sperm whale landed at Agblogamé, near Lomé, on 23 Mar 2012 (Fig. 7). Sex was not recorded but the size suggests it was an adult. The freshly-dead specimen (condition code 3) had probably been captured in a drift gillnet by local, small-scale fishermen and was retained to be used for human consumption. This is the first authenticated record of pygmy sperm whale for the Gulf of Guinea. One dwarf sperm whale [Kogia sima (Owen, 1866)] and 2 Kogia sp. have been reported from Ghana, all bycatches (Van Waerebeek et al. 2009). No Kogia sightings exist for the Gulf of Guinea. Globicephala macrorhynchus Gray, 1846 (short-finned pilot whale) The short-finned pilot whale is the fifth most commonly landed cetacean in Ghanaian ports (Ofori-Danson et al. 2003; Van Waerebeek et al. 2009; Debrah et al. 2010), and is sighted in the Gulf of Guinea (reviewed in Weir 2010). Specimen A 355 cm female short-finned pilot whale was found alive, with slight external bleeding, on a beach near the main jetty of Lomé port, on 28 Sep 2010 (Fig. 8). As a severed rope was tied around the tailstock, an abandoned bycatch was suspected. The animal was refloated and towed out to sea for release by a small Navy tugboat, but it is unclear whether it survived. The short-finned pilot whale (Globicephala macrorhynchus Gray, 1846) is the only Globicephala sp. known in the Gulf of Guinea (Perrin & Van Waerebeek 2007; Weir 2010). Stenella attenuata (Gray, 1846) (pantropical spotted dolphin) Specimen The adult skull of a Stenella attenuata (Fig. 9) captured off Togo’s coast, reportedly by Ghanaian fishermen, was obtained by G. H. Segniagbeto at Gbet-
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Figure 7 An adult-sized pygmy sperm whale (Kogia breviceps) landed at Agblogamé in Mar 2012. The small, falcate dorsal fin, positioned behind midback (shown here) together with the beakless head, conical in dorsal profile and small body size are diagnostic.
Figure 8 A juvenile female short-finned pilot whale (Globicephala macrorhynchus) found alive on a beach near the port of Lomé on 28 Sep 2010. A suspected abandoned catch, the animal was later released. First documented record for Togo.
Figure 9 Cranially adult skull (TG008) of a pantropical spotted dolphin (Stenella attenuata) captured by fishermen from Gbetsogbe. First documented record for Togo.
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sogbé (06°09.145′N, 01°18.383′E) on 2 Jul 2003. The referred specimen is TG008 in the Agbo-Zegue biological collection. Tooth counts are: UR 41, UL 41, LR 40, LL 40. In Ghana S. attenuata accounts for 13.2% of cetacean landings, the second most commonly captured species. Atlantic spotted dolphin Stenella frontalis (G. Cuvier, 1829) seems rare, comprising only 0.5% of cetacean landings (Van Waerebeek et al. 2009; Debrah et al. 2010). Sightings No supported sightings exist for Togo. Ten fishermen from Lomé, Gbetsogbe, Agbodrafo and Aneho, who had attended an introductory course in species identification and made notes while out fishing in 2003– 2004, reported 19% of dolphin groups sighted as ‘spotted dolphins’; we surmise that most of these were probably S. attenuata. Tursiops truncatus (Montagu, 1821) (common bottlenose dolphin) Specimen An adult-sized common bottlenose dolphin stranded (code 3) on a beach near Lomé at 06°07.80′N, 01°14.942′E on 13 Sep 2010, as reported by Commandant de Brigade Issifou Minkaïl Yamoussa (Fig. 10). The cause of death is unknown. K. Okoumassou buried the carcass aiming to retrieve the skeleton later. Leftside tooth counts were UL 19 and LL 19. This is the first specimen record of T. truncatus in Togo. No documented sightings are known. T. truncatus is the third (12.3%) most commonly captured cetacean in Ghana (Debrah et al. 2010). A small group was seen foraging around encircling gillnets set near shore just west of Cotonou, Benin (Van Waerebeek et al. 2009). Delphinus sp. (common dolphin) Specimen On 13 Nov 2003, G. H. Segniagbeto and K. Van Waerebeek examined the beach-worn calvaria of an adult common dolphin (TG005) conserved by a resident from Kotokoukondji. The minumum count (eroded tip) of maxillar alveoli was 41 each side. Deep palatal grooves were diagnostic for the genus Delphinus; however, bone erosion and the lack of cranial measurements impeded species-level identification. The calvaria could not be collected but a low-resolution photo (ventral aspect) is archived. In Ghana, 9.4% (n = 212) of landed cetaceans are long-beaked common dolphins Delphinus capensis Gray, 1828 (Van Waerebeek et al. 2009). Orcinus orca (Linnaeus, 1758) (killer whale) Skipper Barbé described his sighting of a pod of 4 killer whales, including an adult male, a female with calf and a female/immature in Togo’s shelf waters on
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30 Jun 1998. Barbé added having encountered the species a number of times between 1996 and 2001. Several fishermen independently described ‘des orques’ predating on humpback whales. Hammond and Lockyer (1988) listed 3 killer whale sightings from Ghana in Aug 1972. Although unauthenticated, these reports are considered credible given O. orca practically cannot be mistaken. The only supported case from the northern Gulf of Guinea is an adult skull of unspecified origin within Ghana curated at the University of Ghana and examined by Van Waerebeek et al. (2009). Unidentified cetaceans 1. In 1974, a large whale stranded on the beach in front of l’Hôtel de la Paix at Lomé (A. Kokou, pers. comm.). Another whale live-stranded near Lomé Rivages, a few kilometers southwest of Lomé, in Oct 1999. Personnel from the Direction de l’Elevage et de la Pêche refloated the latter. 2. A small, yellowish-gray baleen plate (80 × 32 mm), unfortunately without bristles, was obtained at Lomé’s Marché des Fétishes, Akodésséwa, in Sep 2008. A baleen plate length: breadth quotient of 2.5 seems too broad for minke whale and for now it remains incertae sedis.
Folk knowledge and anecdotal records The Ewe people, indigenous of coastal Togo and eastern Ghana, venerate aquatic mammals and sea turtles, a cultural trait linked to traditional animistic beliefs including voodoo, and typically release accidentally caught animals if alive. In addition, as in Vietnam (Smith et al. 1997), bones of stranded cetaceans are respectfully conserved in shrines, often simple open-air enclosures (Ofori-Danson et al. 2003; Van Waerebeek et al. 2009). Albeit conservation-friendly, this tradition hampered research as the obtention of permission to examine skeletal remains required lengthy negotiations if not incentives, while the acquisition or even photographing of specimens was often prohibitive. Many artisanal fishers interviewed showed a familiarity with the seasonal inshore presence of humpback whales and their calves. Shore-based sightings were described at Adissen (06°11.733′N, 01°27.21′E), N’lessi (06°13.445′N, 01°35.633′E) and Payemé (06°14.417′N, 01°37.628′E). Fishers reported different species of dolphins (gagadolo, giga, atui and takpe) foraging year-round in coastal waters, while some complained of depredation of netted fish. Sport fishing and whale-watching outings off Lomé in 1996–2001 also indicated year-round sightings of common dolphins, bottlenose dolphins and (unspecified)
© 2012 Wiley Publishing Asia Pty Ltd, ISZS and IOZ/CAS
Checklist of the cetaceans of Togo
Figure 10 An adult-sized common bottlenose dolphin (Tursiops truncatus) stranded in early decomposition on a beach near Lomé on 13 Sep 2010. First documented record for Togo.
spotted dolphins Segniagbeto & Van Waerebeek 2010). Barbé further reported groups of 10–40 pilot whales in continental slope waters during periods of high SST (>28 °C), from mid-Feb to the first week of Jun, and a pod of 3 sperm whales approximately 20 nautical miles south of Lomé on 13 Jun 1997. Fishermen from N’lessi who had received basic training reported 42 cetacean sightings in water
