Abstract

Since October 2003 to October 2007, 1,444 gonad samples of the clupeid fishes, Harengula clupeola (false pilchard), Harengula humeralis (redear sardine) and Opisthonema oglinum (thread herring) were collected and analized histologically. These three species are very important as baitfishes for commercial and recreative fisheries in Puerto Rico. The main objectives of the study were to estimate the size at sexual maturity (50% SSM) and to determine the reproductive season of each species in order to establish management measures in the future, if necessary. The 50% SSM estimate for the false pilchard was 75 mm fork length (FL) for males. All individuals larger than 105 mm FL were mature. The estimate for the females was 85 mm FL and all females larger than 105 mm FL were mature. It was determined that this species reproduces year round, showing more activity between March and September. For the redear sardine the maturity size estimates were 93 mm FL and 96 mm FL for males and females, respectively. For this species all males larger than 115 mm FL were mature and all females of more than 110 mm FL were mature. Similar to the false pilchard, the redear sardine reproduces during the whole year but, increased reproductive activity occurs from January to August. The 50% SSM estimate for the thread herring was 132 mm FL for males and 119 mm FL for females. All males and females larger than 190 mm FL were mature. Different from Harengula spp., the thread herring shows a reproductive season more definite that extends from April to September. The vulnerability of these species to fishing pressure during the reproductive season is considerable because during this period migrations to the shore take place. The elimination of the beach seine as a fishing gear in Puerto Rico could be crucial for the conservation of these species.

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