Reproduction of the anthozoan Anemonia sulcata (Pennant, 1777) in southern Spain: from asexual reproduction to putative maternal care

Abstract

Anemonia sulcata (Pennant, 1777) is a common shallow water cnidarian from rocky platform and boulder beaches in southern Spain, where it is a popular seafood item with an increasing fishery. To aid in the management of a sustainable fishery, a study on the reproduction of A. sulcata in the littoral of Malaga (southern Spain) was performed from November 2014 to September 2015, using histological methods. A total of 123 specimens were examined, with a size range (as diameter of the pedal disc) from 1.1 to 48.2 mm. The sex ratio was significantly biased to females, with 1.7 females: 1 male (χ2 = 4.45, p < 0.01). The spermatozoids and oocytes arise from the endodermal cells. The mature oocytes receive nutritive filaments (trophonema) from the endoderm cells. There were zooxanthellae in the mesenteries, tentacles and also inside the oocytes. A gastrula was observed in one individual, as well as several planula larvae in different degree of development in others. Asexual reproduction by internal budding was observed in some individuals. The studied population showed an extended reproductive cycle with a peak of spawning in April. The size and weight of sexual maturity of the studied population were 21.5 mm and 16.5 g, respectively. A positive significant correlation was observed between size and weight of individuals. We suggest that the diameter of the pedal disc should be used as the legal parameter for the management of this fishery, as this measurement is easier to take by fishermen at sea than the weight, the current legal parameter.