J Fish Biol. 2023 Sep 13. doi: 10.1111/jfb.15564. Online ahead of print.
ABSTRACT
A ten-year monitoring program was developed to quantify the population dynamics of long-snouted seahorse population in the Mar Menor coastal lagoon. Based on 985 underwater visual censuses, we estimated the long-snouted seahorse (Hippocampus guttulatus Cuvier, 1829) population size in the Mar Menor Lagoon and its reduction in size in the last decades, as well as the effect of eutrophication crises in 2016 and 2019 on the species. The annual recruitment for the 2013-2020 period was estimated by comparing the relative abundance of early seahorse life stages in the ichthyoplankton. The density ranged from 0.0458 specimens/m3 at the beginning to 0.0004 at the end of the sampling period, showing a statistically significant difference between the three analysed periods (Hgl=2 =14.0, p=0.001). The long-snouted population from the Mar Menor Lagoon exemplifies the impact of fishing activities and human pressure, especially euxinic episodes and habitat destruction. As a result of this, the Mar Menor population has decreased from several million specimens to a few thousand, in only three decades. This species showed considerable resilience, recovering from fishing activity once that it had abated. In contrast, long-snouted seahorse showed high vulnerability to habitat loss and an episodic flooding event. Adult seahorses showed preferences for highly complex habitats, especially Caulerpa prolifera-Cymodocea nodosa mixed meadows and habitats of high complexity and anthropogenic origin, such as harbours, jetties or breakwaters. In contrast, juvenile sseahorses preferred monotonous seabeds with low complexity, such as sandy beds that are characteristic of the Mar Menor Lagoon littoral. This article is protected by copyright. All rights reserved.
PMID:37703094 | DOI:10.1111/jfb.15564
