Abstract


Between August 1995 and August 1997 long line fishing techniques and a bathythermograph were used to correlate sorne physical variables with the spatial distribution of four shark species in 26 fishing cruises off the Nicaraguan Pacific Coast. They were the thresher (Alopias vulpinus), blue (Prionace glaucea), gray (Carcharhinusfalciformis) and harnmer (Sphyra lewim). AH species concentrated in the southeastern Nicaraguan Pacific, at the seasonal upwelling area of Papagayo Gulf. The range of sea sl.\rface temperatures in which the sharks were captured was 25- 28°C. We could clearly associate this physical parameter with shark availability. The vertical distribution of the captured sharks suggests that they occupy termocline levels aboye the 15°C isotherm. Although these species are oceanic, the blue shark was captured inocean waters over the 1800m isobar, while the grey and thresher sharks where close to the continental shelf. Body length in decreasing order are: thresher (210-290 cm, SN = 2'1), blue (60-240 cm, SN = 13) andgray (80- 200 cm, SN = 17).
Keywords: fishery, sh¡p-ks, thermal distribution, Nicaraguan pacific waters