Patterns of coral-reef finfish species disappearances inferred from fishers' knowledge in global epicentre of marine shorefish diversity

In the Philippines, very high fishing pressure coincides with the globally greatest number of shorefish species, yet no long-term fisheries data are available to explore species-level changes that may have occurred widely in the most species rich and vulnerable marine ecosystem, namely coral reefs. Through 2655 face-to-face interviews conducted between August 2012 and July 2014, we used fishers' recall of past catch rates of reef-associated finfish to infer species disappearances from catches in five marine key biodiversity areas (Lanuza Bay, Danajon Bank, Verde Island Passage, Polillo Islands and Honda Bay). We modeled temporal trends in perceived catch per unit effort (CPUE) based on fishers' reports of typical good days' catches using Generalized Linear Mixed Modelling. Fifty-nine different finfish disappeared from catches between the 1950s and 2014; 42 fish were identified to species level, two to genus, seven to family and eight to local name only. Five species occurring at all sites with the greatest number of fishers reporting zero catches were the green bumphead parrotfish (Bolbometopon muricatum), humphead wrasse (Cheilinus undulatus), African pompano (Alectis ciliaris), giant grouper (Epinephelus lanceolatus) and mangrove red snapper (Lutjanus argentimaculatus). Between the 1950s and 2014, the mean perceived CPUE of bumphead parrotfish declined by 88%, that of humphead wrasse by 82%, African pompano by 66%, giant grouper by 74% and mangrove red snapper by 64%. These declines were mainly associated with excess and uncontrolled fishing, fish life-history traits like maximum body size and socio-economic factors like access to market infrastructure and services, and overpopulation. The fishers' knowledge is indicative of extirpations where evidence for these losses was otherwise lacking. Our models provide information as basis for area-based conservation and regional resource management particularly for the more vulnerable, once common, large, yet wide-ranging reef finfish species

A multidisciplinary study of reef-associated fisheries depletion in Philippines

Little is known about long term trends in fish abundance in the most biodiverse marine ecosystem (coral reef) in one of the most marine biodiverse regions on Earth (the Philippines). I analysed finfish family level catch per unit effort (CPUE) data for 1950-2007 from hook-and-line and gillnet based on fishers' knowledge and underwater visual census (UVC) numerical abundance data for 1985-2007 from Pamilacan and Balicasag islands; and CPUE species level landings data for 1983 2005 from Davao Gulf and the Camotes Sea. Linear mixed models and generalised least squares showed that in CPUE data large predators (e.g. Epinephehnae, Lutjanidae, Carangidae and Lethrinidae) and Caesionidae declined the most while in UVC abundances other common target families (e.g. Acanthuridae, Caesionidae and Scaridae) declined the most. Declines in UVC data of large predators (e.g. Epinephelinae, Carangidae and Lethrinidae) were not detected, possibly because these groups were depleted prior to the period as shown by mean abundances of 0-<l per 500m in non-sanctuary areas from 1985 to 2007 at Pamilacan.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Finfish disappearances around Bohol, Philippines inferred from traditional ecological knowledge

Little is known about local extinctions of finfish species in the most biodiverse marine ecosystem in the most marine biodiverse and anthropogenically threatened region on Earth. This paper examines coral reef associated finfish species that disappeared in the catches around the island of Bohol over the period 1950 to 2007, based on the only available data, namely traditional ecological knowledge. Generalized least squares (GLS) tests showed steep declines to zero among species formerly recorded in catches. Finfish species recommended as priority for further monitoring based on life history and disappearances in fish catch are giant grouper (Epinephelus lanceolatus) and African pompano (Alectis ciliaris). Twenty out of the 21 species that disappeared from catches were moderate to very large-bodied, six were slow-growing fish and Four were late-maturing fish. Species of large body size and subject to high fishing pressure may be particularly vulnerable. Traditional ecological knowledge when applied to population dynamics studies can add value to development of new monitoring methods. This knowledge can moreover inform the prioritization of species for fisheries assessment and conservation action

Candidate models for the socio-economic variables depletion.

<p>Candidate models for the socio-economic variables depletion.</p

Response variable, fixed and random effects, dispersion and AIC values of the GLMM and zero-inflated GLMM (ZIGLMM) models for <i>Bolbometopon muricatum</i> and <i>Epinephelus lanceolatus</i>.

<p>Response variable, fixed and random effects, dispersion and AIC values of the GLMM and zero-inflated GLMM (ZIGLMM) models for <i>Bolbometopon muricatum</i> and <i>Epinephelus lanceolatus</i>.</p

Perceived Catch per unit effort (CPUE) ± SE.

<p>Perceived Catch per unit effort (CPUE) ± SE.</p

Life-history covariates included in the final model showing statistical significance and direction of effect (+/-).

<p>Life-history covariates included in the final model showing statistical significance and direction of effect (+/-).</p

Numbers of zero catch reports for species reported in at least two marine KBAs.

<p>Numbers of zero catch reports for species reported in at least two marine KBAs.</p

Covariates included in the final model (see text) for each species showing statistical significance and direction of effect (+/-).

<p>Covariates included in the final model (see text) for each species showing statistical significance and direction of effect (+/-).</p

Target species of fishers in each marine KBA.

<p>Target species of fishers in each marine KBA.</p