Effects of fishing on Holothuria nobilis populations on the Great Barrier Reef

Density and size structure of Holothuria nobilis populations were surveyed in the main area of fishing effort on the Great Barrier Reef. Surveys were carried out for most reefs on three trips between August 1999 and January 2000, Hicks and Davie reefs were surveyed in October 1998.Density data were collected from 16 reefs open to fishing, 4 closed to fishing and 4 reefs with open and closed zones.Size structure of the population was obtained by measuring the body weight of 18-71 animals from each of 6 reefs open to fishing, 3 closed to fishing and 2 reefs with open and closed zones. Animals were weighed to the nearest 50 g.The habitat was recorded: reef flats (the main habitat), fore- and back reefs. Surveys were undertaken to assist in the derivation of sustainable catch rates for this species and were undertaken in the most heavily fished area of the Great Barrier Reef.To establish the effects of fishing on bêche-de-mer stocks and the effectiveness of the two types of zoning protection (reefs which were either open or closed to fishing, and reefs in which zones were open and closed to fishing). Although the black teatfish in the Pacific is correctly referred to as Holothuria whitmaei, H. nobilis was the most commonly recognised name at the time of study and was therefore used in this study.Reefs surveyed: Open to fishing: 13-050, 13-120, 17-065, Agincourt No.4, Arlington, Bowl, Davie, Ellison, Feather, Hicks, McCulloch, Peart, Potter, Ribbon No.10, Ribbon No.8, St. Crispin, Sudbury, TongueClosed to fishing: Agincourt No.1, Michaelmas, Moss, Ribbon No.2With both open and closed zones: Hastings, Opal, Ribbon No.7, Ribbon No.10

本研究对大堡礁（Great Barrier Reef）核心捕捞作业区内的黑乳海参（Holothuria nobilis）种群密度与体型结构开展了系统性调查。调查于1999年8月至2000年1月间分3个航次完成，覆盖绝大多数调查礁盘；希克斯礁（Hicks Reef）与戴维礁（Davie Reef）则于1998年10月单独完成调查。

本次密度调查共获取16个开放捕捞礁盘、4个禁捕礁盘以及4个兼具开放与禁捕分区的礁盘的有效数据。种群体型结构数据则通过称重获取：共在6个开放捕捞礁盘、3个禁捕礁盘、2个兼具分区的礁盘内取样，单礁取样量为18至71头个体，称重精度精确至50克。

调查同时记录了该种群的栖息生境类型，包括礁坪（主要栖息生境）、礁前斜坡与礁后斜坡。

本次调查的核心目标有二：其一为推导该物种的可持续捕捞率；其二为评估大堡礁捕捞压力最高区域内两类分区保护措施的实施效果——即完全开放捕捞或完全禁捕的礁盘，以及兼具开放与禁捕分区的礁盘，以此明确捕捞活动对食用海参（bêche-de-mer）种群的影响。

需特别说明的是，太平洋海域的黑乳海参正确学名为Holothuria whitmaei，但在本研究开展时期，Holothuria nobilis是该物种更为广泛认可的通用名称，故本研究沿用该名称。

本次调查涉及的礁盘清单如下：
1. 开放捕捞礁盘：13-050、13-120、17-065、阿金科特4号礁（Agincourt No.4）、阿灵顿礁（Arlington）、鲍尔礁（Bowl）、戴维礁（Davie）、埃尔利森礁（Ellison）、费瑟礁（Feather）、希克斯礁（Hicks）、麦卡洛克礁（McCulloch）、皮尔特礁（Peart）、波特礁（Potter）、丝带10号礁（Ribbon No.10）、丝带8号礁（Ribbon No.8）、圣克里斯平礁（St. Crispin）、萨德伯里礁（Sudbury）、通格礁（Tongue）
2. 禁捕礁盘：阿金科特1号礁（Agincourt No.1）、迈克尔马斯礁（Michaelmas）、莫斯礁（Moss）、丝带2号礁（Ribbon No.2）
3. 兼具开放与禁捕分区的礁盘：黑斯廷斯礁（Hastings）、欧泊礁（Opal）、丝带7号礁（Ribbon No.7）、丝带10号礁（Ribbon No.10）