Growth and related traits of the sheepswool sponge (Hippospongia lachne): practical and theoretical considerations

Abstract

2 Changing Oceans Research Unit Institute for the Oceans and Fisheries University of British Columbia 2202 Main Mall Vancouver, British Columbia V6T 1Z4, Canada 3 Institute of Environment and Department of Biological Sciences Florida International University 3000 NE 151 Street, AC1-213 North Miami, Florida 33181 Abstract—Fisheries for Caribbean sponge species began in the mid-1800s and landings peaked around the early 1900s before crashing because of a combination of overexploitation, disease, and hurricanes as well as, later, the introduction of artificial sponges. Still, artisanal sponge fisheries remain in Florida and areas of the Caribbean like The Bahamas, but none of those fisheries or the sponges upon which they depend are well studied. On the basis of data and information published by J. Storr in 1964 as well as of our own data, von Bertalanffy growth parameters were estimated for the most commercially valuable Caribbean sponge, the sheepswool sponge or wool sponge (Hippospongia lachne), along with related statistics, notably longevity. Also, morphological dimensional constraints that are likely to limit the supply of oxygen deep within this and other nearspherical sponge species are presented, along with the sponges’ evolutionary and ontogenic responses to these constraints. These considerations are also illustrated with data from species other than the wool sponge and are consistent with a general theory of growth for waterbreathing ectotherms, the gilloxygen limitation theory. The information provided herein should be useful for quantifying the ecosystem effect of sponge fisheries in Florida, The Bahamas, and elsewhere and for improving the management of sponge fisheries and mariculture worldwide.