Larviculture, allometric growth patterns, and gape morphology of the Florida blenny, Chasmodes saburrae

Abstract

Blennies are cryptobenthic reef fishes (CRFs) that occupy a critical functional group in the trophodynamics of their respective ecological systems and for many of these species there has been renewed interest in their diversity and evolution. Here we provide a robust larviculture methodology for combtooth blennies (f. Blenniidae), that may have applications for both ornamental aquaculture and scientific research. Larval ontogeny, pigmentation, and allometric growth patterns, including gape morphology, of the Florida blenny, Chasmodes saburrae, from the northern Gulf of Mexico (GoM) are described from a complete larval series from hatch to settlement (notochord length/standard length, NL/SL = 3.37–14.49 mm; 1–21 days post hatch, dph). Larvae/settlers were assigned intervals of development using a suite of morphological characters. Allometric growth rates and inflection points of rate change were computed with piecewise linear regressions. Pigmentation and general patterns of development followed that of other blenniid species in the GoM. Growth of all but one morphometric character measured followed a positive allometric growth rate relative to size (NL/SL) after hatching and followed a mostly biphasic growth pattern with inflection points corresponding to phenotypic changes during notochord flexion or prior to settlement and the completion of metamorphosis. A feeding gape size of 26.6% that of maximum gape size was calculated using size at first feeding of prey items and used to estimate an optimized feeding protocol. Based on this gape informed diet, larger and more nutrient rich prey items may be implemented in the feeding protocol between four and eight days earlier than previous study recommends. Captive breeding techniques used during this study show the practical advantages of culturing blenniid larvae with life histories similar to C. saburrae compared with that of most marine fishes currently being cultured and suggests that blenniid larvae may serve as sensible candidates as a model study group for marine teleosts.