WIOMSA-CORDIO spawning book Full Doc 10 oct 13.pdf

The sizes of E. fuscoguttatus aggregating in Kenya conform to those of reproductively active E.fuscoguttatus on the Great Barrier Reef (GBR), Australia. Pears et al. (2006) report that this speciesis a long-lived protogynous hermaphrodite with males ranging in size from 68.3 to 92.5 cm TLand mature females from 32.0 to 85.5 cm TL. No fish smaller than 56-60 cm TL was observedat the Kenyan aggregations. The change in size frequency distribution at the aggregation sitesbetween the summer spawning and non-spawning winter period, with fish greater than 90 cm TLonly observed during November-January suggests that the largest males migrate to the aggregationsites to spawn. These may be the males that dominate gaining access to females, as seen in othergroupers (Samoilys and Squire 1994, Samoilys 1997b, Robinson et al. 2008b).Management implicationsE. fuscoguttatus demography of long life (40+ years), late onset of sexual maturity in females (at 9years), increasing female fecundity with age over a reproductive lifespan of more than 30 yr (Pearset al. 2006) do not confer resilience to fishing. In fact, such life history traits are all closely correlatedwith vulnerability to extinction (Mace and Hudson 1999; Reynolds et al. 2003; Dulvy et al 2003).These demographic factors, coupled with heavy fishing pressure and the many unmanaged fisheriesfor this grouper, led to its Near Threatened classification on the Red List (IUCN 2011). Thefact that E. fuscoguttatus also forms spawning aggregations that appear to be predictable in timeand place increases the vulnerability of this species (Sadovy de Mitcheson et al. 2008). This isparticularly so in Kenya where coastal fishing is not regulated by size class (both minimum andmaximum size class fishery restrictions would be beneficial for this species). Additionally, the fullyprotected marine areas (the nationally gazetted Marine Parks) are small, protecting only 8.6% of thecountry’s coral reef area (Spalding 2001; Wells 2006) in contrast with global recommendations inthe order of 30% (Fernandes et al. 2005). Recent reports of reproductive movement and estimatesof catchment area for this species suggest large-scale marine parks are needed to protect populationsof this species (Rhodes et al. 2012).Local artisanal catches of E. fuscoguttatus have dwindled in recent years (see Chapter 3; Samoilyset al. 2011b) to the extent that we were unable to collect adequate gonads for reproductiveassessment, or assess population abundance through catch rate analysis. Population abundancesurveys (on SCUBA to 30 m) on eastern African reefs also show that this species is rare (Samoilysunpubls. data), possibly in response to historical targeted fishing of aggregations of this species. Ourindicator-based vulnerability analysis of the spawning aggregations of this species also revealed thatthey have relatively high vulnerability (see Chapter 11).Given the combined factors of life history, small aggregation size and low cover of protected areasat a national scale, there is a need to institute additional management if this species is to persistalong the southern Kenyan coastline. The aggregation sites documented here are not managed orprotected, despite one occurring within the nationally gazetted Diani-Chale Reserve. This Reserveis not enforced due to strong local opposition from fishers. Low aggregation sizes may be theresult of past fishing at aggregation sites or on the population as a whole. Further, we know fromstudies in Australia (Pears et al. 2006, 2007) that E. fuscoguttatus females need to breed for 30+years to reach their full reproductive potential and our results suggest that spawning aggregationsare important sites for these females to spawn. We therefore recommend that management of thesesites be discussed as a matter of priority with all stakeholders, including local fishing communities,the hotel/dive tourism industry and the government’s Kenya Wildlife Service (KWS) with authorityover the Diani-Chale Reserve. Conflict between different users in this area has been ongoing formany years, but recent mitigation training and discussions have provided options for resolvingthese difficulties (Watson and Ater 2011). To protect this valuable and threatened grouper, it isimportant that management options, including permanent no-take zones, are discussed for thespawning aggregation sites within the Reserve.74