Search

This contribution presented stock assessments for 10 fish and 2 squid populations exploited by Chinese, South Korean, and Japanese fishing fleets in the Tsushima Warm Current region, i.e., Southwest Japan and East China. The methods used were a Monte Carlo method (CMSY) and a Bayesian state-space implementation of the Schaefer model (BSM), based on published time series of catch and abundance data (SSB and CPUE). Results showed that 2 fish stocks, Japanese jack mackerel (Trachurus japonicus) and yellowback sea-bream (Dentex hypselosomus), had a healthy status, while daggertooth pike conger (Muraenesox cinereus) appeared to have collapsed. The other 9 stocks showed varying degrees of overfishing. The cooperation of several countries would be required to recover the fishery resources in the Tsushima Warm Current region.

Maximum sustainable yield (MSY) of squid fishery (including all species of squids) from Pakistani marine waters was calculated by using the catch and effort data from 1998 to 2010. Reported squid capture production totaled 40,390 metric tons (mt) during this period. The highest catch was 5,062 mt in 1999 while the lowest catch, 2,130 mt, was observed in 2003. Two specialized computer applications viz. CEDA and ASPIC were employed to statically evaluate the data. CEDA computer package includes three surplus production models (SPMs): the Fox, Schaefer and Pella Tomlinson models. Each model further uses three error assumptions i.e. log, log normal and gamma. An IP (initial proportion) of 0.6 was used because the initial catch was about 60% of the maximum catch. Computed MSY and CV values from the Fox model with log and log normal error assumptions were 2,401 mt (0.314) and 2,553 mt (0.250) correspondingly. However, for the Schaefer and Pella Tomlinson models, by using log and log normal assumptions, MSY and CV values remained 2,416 mt (0.235), 2,746 mt (0.072) and 2,416 mt (0.292) and 2,746 mt (0.063) in that order. All the SPMs with gamma error assumption did not produced interpretable result. In ASPIC, we used two models i.e. Fox and Logistic. Computed MSY with CV remained 2,659 mt (0.093) and 2,664 mt (0.065) respectively. CEDA computer package showed better fit to the data in terms of goodness of fit (R[sup 2]) values. CEDA results, for the Schaefer and Pella Tomlinson models with log assumption, both with high R[sup 2] values (0.607), suggest that MSY of squid fishery in Pakistani marine waters is around 2,400-2,500 mt. Current of catch of this fishery resource is higher than its MSY. Thus, overall landing of this fishery resource must be reduced through some effective management measures in order to conserve this resource for future. [ABSTRACT FROM AUTHOR]

Anderson, S. C., Branch, T. A., Ricard, D., and Lotze, H. K. 2012. Assessing global marine fishery status with a revised dynamic catch-based method and stock-assessment reference points. – ICES Journal of Marine Science, 69: .The assessment of fishery status is essential for management, yet fishery-independent estimates of abundance are lacking for most fisheries. Methods exist to infer fishery status from catches, but the most commonly used method is biased towards classifying fisheries as overexploited or collapsed through time and does not account for still-developing fisheries. We introduce a revised method that overcomes these deficiencies by smoothing catch series iteratively, declaring fisheries developing within three years of peak catch, and calibrating thresholds to biological reference points. Compared with status obtained from stock-assessment reference points for 210 stocks, our approach provides a more realistic assessment than the original method, but cannot be perfect because catches are influenced by factors other than biomass. Applied to FAO catches, our method suggests in 2006 32% of global fisheries were developing, 27% fully exploited, 25% overexploited, and 16% collapsed or closed. Although less dire than previous assessments, this still indicates substantial numbers of overexploited stocks. Probably because median exploitation rate decreased since 1992, our catch-based results do not reflect recent stabilization of assessed-stock biomass. Whether this outlook also applies to unassessed stocks can only be revealed with increased or more representative collection of biomass- and exploitation-rate trends. [ABSTRACT FROM PUBLISHER]

The results of the seasonal analysis of the chemistry of rain, fog and surface water of central India for the two years: June 1996 to May 1998 are presented. A total of 636 rain water samples, 146 fog water samples and 226 surface water samples of 8 locations: namely, Ambikapur, Baikunthpur, Korba, Bilaspur, Raipur, Bhilai, Dallirajhara and Kanker, from different sites were collected for the present study. This paper documents the occurrence of acidic rain and fog events and their effect on surface water pH and aquatic life in central India. Most of the rain and fog water samples collected from Baikunthpur and Korba sites were found to be acidic in nature (i.e. pH < 5). The volume weighted mean pH of rain and fog water samples of these sites was 4.8 and 4.4 with lowest pH 4.4 and 4.0, respectively. However, samples from Ambikapur, Bilaspur, Raipur and Bhilai were slightly acidic and their pH values were always around 5.8. One reservoir (mean pH 5.8) and two stop dams (mean pH 4.4 and 4.2) in Baikunthpur area were found to be acidic. The effect of acidification of water on metal-accumulation in muscles of fishes was studied. Concentrations of Al, Hg, Mn, Cd and Pb were higher in fish from acid, than from less acid waters. Causes of acidification of the atmospheric water and surface water are critically discussed. [ABSTRACT FROM AUTHOR]

Abstract: A paper by Pauly and Froese published in Marine Policy includes several misrepresentations concerning a paper published in Nature by Branch et al. on the tropic fingerprint of marine fisheries. The purpose of this Short Communication is to examine and refute their claims. [Copyright &y& Elsevier]