The marine environment has traditionally been considered to be resilient to human impacts. However, concern over growing threats to marine biodiversity has led to a renewed effort to assess and quantify risks to marine species. This study assesses threats to the subfamily Epinephelinae of the Serranidae (groupers), a commercially and ecologically important group of predatory fish which are heavily exploited throughout their range. Eighty-five tropical species of the subfamily are examined in detail and classified according to 1996 IUCN Red List categories. Thirty-seven species (43.5%) are considered Threatened, of which two (Cromileptes altivelis and Epinephelus akaara) are Endangered, and the remaining 35 are Vulnerable. Thirty-four species (40%) are listed as Lower Risk and do not appear to be under immediate threat. Fourteen species (16.5%) are Data Deficient. Most of the threatened species are wide ranging. Large range size and the production of abundant, dispersive offspring are characteristics of groupers that have previously been considered to make them unlikely candidates for extinction. However, rapidly intensifying fisheries employing habitat-destructive gears now encompass vast areas of the tropics, putting many species at risk. Members of the genera Epinephelus and Mycteroperca were found to be particularly at risk, probably due to their large body sizes, long life-span and late reproduction.

The threatened status of groupers (Epinephelinae)

Osteological development and abnormalities of the vertebral column and caudal skeleton in larval and juvenile stages of hatchery-reared Senegal sole (Solea senegalensis)

Development of an optimal microalgal diet for the culture of the calanoid copepod Acartia sinjiensis: Effect of algal species and feed concentration on copepod development

Aquaculture of groupers is carried out in tropical and subtropical areas throughout the world, but most production is from Asia, with three countries responsible for an estimated 92% of global production: China (65% of total production), Taiwan Province of China (17%) and Indonesia (11%). We calculate that there are at least 47 grouper species plus 15 grouper hybrids that have been trialled or are currently aquacultured. While grouper aquaculture has undoubtedly provided positive social and economic benefits to coastal communities in Asia, practices associated with grouper aquaculture have also led to widespread concerns regarding its environmental impacts. This paper reviews environmental, economic and social impacts of grouper aquaculture within a sustainability science framework. An update, building on early technical reviews of grouper aquaculture, was used to identify the main environmental, economic and social impacts. The main environmental impacts identified were as follows: seedstock sources, particularly the use of wild-caught postlarval or juvenile fish as seedstock; the use of 'trash' fish as the major feed source; and water quality and substrate impacts of sea cage aquaculture. Significant economic and social impacts arising from grouper aquaculture include employment and income generation, but the economic impacts of disease outbreaks are significant, reducing fish survival to harvest size to around 50-70%. Current approaches to ameliorate negative impacts include the following: development and implementation of better management practices (BMPs) at national level, and the development of a global ecolabel certification scheme by the Aquaculture Stewardship Council. Both these approaches have significant constraints, particularly when applied to small-scale farmers who produce the bulk of farmed grouper. We conclude that there is a need for improved higher level coordination between the major producer countries to address identified sustainability constraints to grouper aquaculture. © 2017 Wiley Publishing Asia Pty Ltd.

A review of grouper (Family Serranidae: Subfamily Epinephelinae) aquaculture from a sustainability science perspective

The osteological development of elements forming the oral cavity was examined in early stage larvae of the grouper,Epinephelus coioides, from hatching to 242.5 hours after hatching. By the time of initial mouth opening, at 54 hours after hatching, the fundamental elements, composed of the trabecula, some components of the lower branchial and hyoid arches, the quadrate and symplectic-hyomandibular cartilages, maxilla and Meckel's cartilage, had appeared. No further elements were observed until 165 hours after initial mouth opening, except some components in the lower branchial arch and head region. The appearance of new elements and initial ossification of existing cartilage occurred thereafter, but all elements related to feeding either had not appeared or had not started ossifying until 188.5 hours after initial mouth opening. Based on the morphology and developmental modes of these elements, the feeding mode of grouper larvae was considered to be “sucking/grasping.” However, the appearance and ossification of elements occurred slowly, with no transitional phase from sucking to grasping modes of feeding being observed during the study; such delayed development of the feeding-related bony elements was considered to be a cause of the difficulty in rearing early stage grouper larvae.

Why is grouper larval rearing difficult?: an approach from the development of the feeding apparatus in early stage larvae of the grouper,Epinephelus coioides

The osteological development of the feeding apparatus was examined in early stage larvae of laboratory-reared seabass,Lates calcarifer At initial mouth openings 40 hours after hatching, the larvae were equipped with the fundamental elements forming the oral cavity, such as the trabecular roof, the lower branchial and hyoid arches forming the floor, the quadrate and symplectic-hyomandibular cartilages making up the sides, and the maxilla and Meckel's cartilage bordering the jaws The cleithrum appeared almost simultaneously The mechanics of creating a negative pressure in the oral cavity, which results in a “sucking” mode of feeding, were elucidated from these elements During a period from 50–60 to 100–110 hours after initial mouth opening (HAMO), new elements such as the premaxilla and jaw teeth appeared, and the ossification of existing elements started The new elements apparently enabled the larvae to “grasp” food organisms, in addition to the already existing and increasing sucking ability, from 100–110 HAMO

Osteological development of the feeding apparatus in early stage larvae of the seabass,Lates calcarifer

The osteological development of elements comprising the oral cavity and fins was examined in early stage larvae of laboratory-reared milkfish,Chanos chanos, from hatching to 200 hours after hatching. Fundamental elements of the oral cavity had developed by the time of initial mouth opening, 54 hours after hatching. The oral cavity was long and cylindrical, with a short, robust Meckel's cartilage, and robust quadrate and symplectic-hyomandibular cartilages. The initial ossification of existing elements and addition of new elements occurred between 120–146 hours after initial mouth opening (HAMO), whereas the cartilaginous basihyal and caudal fin-supports appeared at 37.5 and 61.5 HAMO, respectively. Based on the morphology and developmental patterns of characters examined in this study, the feeding mode of early stage larval milkfish was considered to be “straining,” with an improvement in feeding ability occurring between 120–146 HAMO.

Riza Ordonio-Aguilar

Papers

Why is grouper larval rearing difficult?: an approach from the development of the feeding apparatus in early stage larvae of the grouper,Epinephelus coioides

Osteological development of the feeding apparatus in early stage larvae of the seabass,Lates calcarifer

Morphological aspects of feeding and improvement in feeding ability in early stage larvae of the milkfish,Chanos chanos