ghana climate change vulnerability and adaptation assessment

completely dominate trawl catches before it collapsed. Its appearance is likely related to the availability of newlycreated “niche space” because of the wholesale removal of other demersal species by trawl fisheries. Otherexamples of symptoms of instability include the decline and subsequent recovery of round sardinella, Sardinellaaurita, populations (Pezennec 1995), and the increase in abundance of cuttlefish, Sepia officinalis and globefish,Lagocephalus laevigatus (Ramos et al., 1990; Koranteng, 1998).Multivariate analysis of demersal catch composition in Ghana from 1972 until 2008 is also informative (Finegoldet al., 2010). The most significant shift occurred between 1988 and 1989. This coincides with the crash of thetrigger fish fishery and an increase in burrito catch. The increase in burrito catch might reflect fishers targetingburrito as a replacement for trigger fish. The second shift in catch composition occurred between 1997 and 1998and is driven by a decline in burrito catch and an increase in cassava fish catch. The continuing change in catchcomposition to 2008 (last sample analyzed) is driven by the increasing dominance of cassava fish in the catch.Although these community shifts cannot with total certainty attributed directly to fishing pressure, demersalcommunities typically are more stable than pelagic communities. Shifts in community structure caused byenvironmental factors (e.g., upwelling strength) are unlikely to lead to the permanent changes seen here. Similaranalysis conducted on pelagic catches in Ghana showed no long-term consistent changes in composition(Finegold et al., 2010). The shifts apparently coincide with the removal of species dominant in catches, and assuch, suggest fishing pressure as a principal cause of compositional changes (Finegold et al., 2010).FISHING EFFORT AND TECHNOLOGY CHANGESOne of the significant shortfalls of fishery regulation and management in Ghana is a failure to document fishingeffort among fleets. However, at the coarsest level, fleet size provides a measure of fishing effort. Increasednumbers of active fishing vessels will likely lead to greater fishing pressure on resources. In Ghana, all fleets haveexpanded, some substantially so, since the 1990s, but the expansion is not reflected in total landings. To thecontrary, as fleet size increased, catch has dropped. This coarse level of measurement is not the whole story, but itis a warning sign regarding the state of resources (Finegold et al., 2010).Another indicator of fishing effort is time spent fishing or catch per unit effort (CPUE). If vessel numbersincrease, but the time spent fishing by each vessel decreases, then vessel numbers viewed in isolation mayrepresent an overestimate of the change in fishing effort. Data suggest a severe decline in CPUE for the inshorefleet, but no particular trends for the canoe or industrial fleet (Finegold et al., 2010). Although an improvementbeyond simple measures of fleet size, measuring effort only as the number of fishing trips, which is howGhanaian fisheries authorities measure effort, can be misleading in comparing across decades. Changes intechnology and fishing practices can have a dramatic impact on effective fishing effort with no associated changein number of fishing trips (Finegold et al., 2010).Fishers in Ghana have adopted a number of changes to their fishing practices that could substantially increase theeffective fishing effort of a single trip. In the canoe and inshore fleets in particular, continued innovation andchange have massively increased fishing power, even in the last decade. Among these are the use of outboardmotors, changes in net type, net construction, or net size, and light fishing (Finegold et al., 2010).Outboard motors and increased travel: Outboard motors allow fishers to travel great distances and track andexploit schools of small pelagic fishes as they move seasonally (Finegold et al., 2010). Similarly, gill netters or linefishers using outboard motors can target the relatively sedentary demersal stocks and maintain catches despitedwindling fish stocks. In Ghana, as shallow water stocks declined, outboard motors allowed canoe fishers to gofarther along the coast and offshore to find new fishing grounds as others are depleted, a process termed serialdepletion of a fishery. Over the last 10 years in the Western Region, interviews with fishers revealed that today onaverage they travel 2.7 times longer to get to fishing grounds than they did only 10 years ago (Fig. 6.7, Finegold etal., 2010). Given the increase in engine power over the past three decades, the increase in distance which theymust travel to find fish would be even higher. Serial depletion masks fish stock declines until no fishers cannotlocate productive fishing grounds, at which point CPUE will decline abruptly and severely. The shift to higherpower, more efficient engines (i.e., 23-30 hp in 1981 to 40 hp engines, today) and improved propellers likelyGHANA CLIMATE CHANGE VULNERABILITY AND ADAPTATION ASSESSMENT 111