CalCOFI Reports, Vol. 27, 1986 - California Cooperative Oceanic ...

MacGREGOR: SEEASTES ABUNDANCECalCOFI Rep., Vol. XXVII, 1986TABLE 3Rockfish Larvae 14-Year Annual AveragesCalCOFIline606367707377Total (60-77)8083879093Total (80-93)Number(billions)16,04415,77912,6855,3294,2016,15960,1977,47612,89616,3269,7915,0945 1,583Percent11.84111.6469.3623.9333.1014.54644.4295.5189.51812.0497.2263.76038.071Icz0tmU\ JAN-FEE\\,P'/'MAR-APRA/97100103107Total (97-107)110113117120Total (110-120)123127130133137Total (123-137)140143147150153157Total (140-157)Total (60-157)3,2752,9731,7751.4199,4421,4482,0143,9442,1829,5881,33688 15798245394,1591286423768817522135,4912.4172.1941.3101.0486.9691.0691.4862.9111.6107.0760.9860.6500.4280.6080.3983.0700.0940.0470.1750.0500.0060.0130.385100.000high spawning effort and/or low early mortality ratherthan random fluctuations resulting from inadequatesampling.The 14-year average number of larvae by CalCOFIline (Table 3) shows high abundance levels in the SanFrancisco-Monterey area (lines 60-67). These linesaccount for 33% of the larvae found in the main surveyarea (30 lines, 60-157). Sparse data for the six linesnorth of line 60 (lines 40-57) indicate a populationequal to about 75% of the population in the arearepresented by the six lines 60-77, with about a third oftF lo;060-77 80-93 97-107 110-120123-137CalCOFl LINESFigure 2. Percent of total year's rockfish spawning occurring in January/February and MarchiApril for five areas as measured by larvae (14-yearaverage).these larvae found on line 57. Along the exposed coastsouth of Monterey (line 70) the larval abundancedecreases to Point Conception (line 80). In the ChannelIslands area (lines 83-90) larval abundance again increases.These three lines account for 29% of the larvaefound in the main survey area. The number of larvaecontinues to decrease southward to line 157 with onesmaller increase in the area around and north of PuntaEugenia and Cedros Island (lines 113-120).The spawning season appears to be later farthersouth (Figure 2). April is the peak spawning month offMexico (lines 97-137). This area accounts for only17%% of the total average yearly production ofrockfish larvae, in contrast to 82%% for U.S. waters(lines 60-93), which tends to mask this seasonalphenomenon (Table 3). The increase in late spawningin the more southern areas is probably due to increasedproportions of late-spawning species of rockfishes likethe Mexican rockfish and the subgenus Sebastomus(Chen 1971), which become relatively more abundantin the rockfishes' southern range.Estimates of the numbers of all rockfishes, S.jordani, and S. macdonaldi were calculated by monthand line for 1956, 1966, 1972, and 1975, and of S.paucispinis and S. levis for 1956, 1969, 1972, and1975'. A summary of the estimated larval abundanceby year and month (Table 4) shows that the seasonaldistribution of all rockfish larvae for the 5 selected'Tables to be issued as an administrative report of the Southwest FisheriesCenter.124