CCAMLR

CCAMLR adopted a new conservation measure in 2007 (CM 22-06) to ensure that significant adverse impacts of bottom fishing gear on Vulnerable Marine Ecosystems (VMEs) are avoided. Due to the high levels of uncertainty surrounding both the evidence of VME presence and the consequences of interaction with different types of gear, a risk management framework is proposed, similar to that which has been used successfully by IMAF to minimise the effects of longline fishing mortality on seabirds. The aim of this risk management is to avoid significant adverse impacts on VMEs from bottom fishing activities. The framework consists of four steps: (1). Risk analysis of current and proposed fishing activities; evidence of potential VMEs; scale of interactions between fishing activities and VMEs; impact of interactions on VMEs; and recovery potential of VMEs. (2) Risk evaluation. Combine information on likelihood and consequences of interactions of bottom fishing gear with VMEs and associated uncertainties from risk analysis to produce risk metrics. (3) Risk elimination or mitigation. Unacceptable levels of risk from bottom fishing activities to VMEs must be eliminated or reduced to acceptable levels through the use of management measures including, inter alia, closed areas around identified VMEs, open and closed management areas, bycatch limits for VME-forming organisms, gear modification or spatial distribution of fishing effort. (4). Review. All of the above steps should be reviewed regularly to ensure that all relevant or new information has been included, appropriate scientific research and data collection plans are in plan and that risk mitigation measures are successful in their implementation.

Tag recapture rates in new and exploratory Dissostichus spp. fisheries in the southern Indian Ocean sector of the CCAMLR area are examined. In particular, the potential for tagging programs in new and exploratory fisheries to yield sufficient data to be of use in determining TAC’s in the early stages of fishery development is considered. Scenarios are developed using a range of tag release rates, tag detection rates, natural mortality, fish movement out of the fishery, and IUU removals in order to estimate the expected numbers of tag returns. Even under “worst case” assumptions, tag recaptures are still expected to be considerably higher than currently observed in Divisions 58.4.1 and 58.4.2. If current tag recapture rates continue, tag-based assessments of stock status 58.4.1 and 58.4.2 are likely to remain uncertain in the short to medium term, and fishing should remain focussed in areas where tag releases have been concentrated until these uncertainties can be addressed.

New Zealand proposes to conduct a scientific research survey during the austral winter in CCAMLR SSRUs 88.1B, 88.1C and, ice permitting, 88.1G in 2008/09, as the first in a three year time series. The proposal is for a targeted longline survey designed to cover critical gaps in the knowledge of the life cycle of D. mawsoni in the Ross Sea by collecting biological samples from a broad spread of locations across the northern Ross Sea during the austral winter. The survey is designed to collect information that should assist in the understanding of the early life history and reproduction of Dissostichus mawsoni in the Ross Sea region. In addition, tag data collected will give additional information on the spawning movements of mature D. mawsoni. The results of the research will lead to improved estimates of length/age of maturity, proportion mature that spawn, and contribute to an improved understanding of the Ross Sea D. mawsoni stock structure. Data collected during the survey will provide information that is likely to directly influence future assessments of D. mawsoni. The proposed research is in accordance with Conservation Measures 24-01, 33-03, 41-01 and 41-09.

The Fouth Meeting of the ACAP’s Advisory Committee was held in Cape Town, South Africa from 22 – 25 August 2008. It was preceded by a meeting of the Seabird Bycatch Working Group (SBWG) on 17-18 August 2008. This paper provides a report on the SBWG meeting. The Working Group reviewed methods to reduce seabird bycatch in trawl fisheries, and noted that the body of work investigating and documenting mitigation measures in trawl fisheries is significantly less advanced than for longline fisheries. Consequently, new developments in this field in recent years are few. Seabird interactions with trawl vessels fell into two broad categories: those focused on the trawl warps, and those focused around trawl nets. For reducing seabird strikes on trawl warps, the use of bird-scaring lines has been proven to be the most effective mitigation device in the trawl fisheries in which comparative studies have been undertaken. However, the retention or strategic management of fish waste (offal and discards) was recommended as the most effective primary measure for bycatch reduction, and should be viewed as the best long-term solution to reducing seabird bycatch in trawl fisheries. Coincident with effective fish waste management, operational measures such as cleaning the net prior to shooting and reducing the time the net is on the surface at shooting and hauling should be viewed as best practice measures and incorporated into routine fishing activities. While a number of methods have been trialed to reduce the incidence of warp strikes, there continues to be the need for more work on effective measures for reducing seabird interactions with trawl nets. The SBWG also reviewed demersal longline mitigation methods. Two tables were developed that summarised bycatch mitigation measures for demersal longline fishing, and identified knowledge gaps and research priorities for this gear type. These tables were subsequently endorsed by the ACAP Advisory Committee as representing the current best scientific advice of the SBWG. The SBWG engaged in extensive discussion regarding the Advisory Committee’s collection of seabird bycatch data from the Parties. Dr Keith Reid from CCAMLR described the CCAMLR data submission and management system, and the fine scale analysis at the level of the fishery, by area, gear type and by vessel, that is carried out by CCAMLR on both target and bycatch species. The Working Group noted the comprehensive nature of the data collection and assessment process that has been developed by CCAMLR and agreed that it formed a useful model for ACAP, noting that an observer program with high levels of coverage had been critical to understanding bycatch problems and had been key to CCAMLR’s success in reducing bycatch in its fisheries. The model was entirely relevant to other RFMOs but could also be adopted by ACAP for assessment of summary bycatch information provided by ACAP Parties.

The paper updates Fenaughty and Bennett (2005), Longlining Operations on New Zealand Autoline Vessels Fishing for Toothfish in CCAMLR Waters. Additional information is included listing and discussing circumstances and scenarios occurring with the method. A definition of the fundamental unit of gear (a ‘line’) for longlines is proposed for the purposes of regulation and management. Current Conservation Measures dealing with longline fisheries carried out within the Convention Area are reviewed and changes are suggested clarify understanding of these measures. The paper includes a recommendation for a review of Annex 41-01/B (2007) governing research within exploratory fisheries by WG-FSA with a view to assessing the option of simplifying this Measure in a similar manner to that successfully implemented in the exploratory fisheries in Subareas 88.1 and 88.2.

At CCAMLR-XXVI the Working Group on Fish Stock Assessment (WG-FSA) noted a lack of specific reference material for the identification of benthic invertebrates in areas specific to which observers carry out their activities (SC-CAMLR-XXVI: Annex 5, paragraph 6.32). To improve the standard of observer identifications and also to assist in the identification of vulnerable areas, the Scientific Committee requested that guides be prepared for the identification of benthic organisms (SC-CAMLR-XXVI: paragraph 4.190). In response to this recommendation Australia has developed the “Field identification guide to Heard Island and McDonald Island (HIMI) benthic invertebrates”. This Fisheries Research and Development Commission (FRDC), Australian Fisheries Management Authority (AFMA) and industry funded production is first of its kind for the region, and is intended to be used as both a training tool prior to deployment at-sea, as well as for use by trained observers to make accurate identifications of invertebrate by-catch when operating in the HIMI region. Based on available data, this publication will include instructions to observers for collection of benthic organisms at sea, quick-reference pictorial guides to invertebrate phyla, common species and CCAMLR identification codes, and detailed identification notes for each phylum including representative images for more than 400 benthic organisms identified from the HIMI region thus far. This guide will enable observers to gather invertebrate by-catch data at higher taxonomic resolutions. We encourage the development of similar guides for training purposes and at-sea use by observers in other CCAMLR designated fisheries and that CCAMLR consider adopting the numerical Integrated Taxonomic Information System (ITIS) as an interim coding system to improve the resolution of benthic by-catch data.

During a longline survey on BANZARE Bank (Division 58.4.3b) in May 2008, an in-line video camera recorded the interactions between the main line and the benthos during setting and hauling. Footage revealed that after setting the line moved very little, despite cross currents. During hauling, the section of line visible to the camera swept sideways, interacting with sessile benthic organisms before leaving the seafloor. Based on an estimate of the rate of sideways movement, the total time sideways movement occurred before the line lifted off the seafloor, the total length of the line and the total time to retrieve the line, we estimate that up to 0.122 km2 of seafloor was swept by the line while it was being retrieved. Consequently the area of seafloor affected by demersal longlines is shown to be comparable with that of demersal trawls. We also provide evidence that benthic fauna that are vulnerable to longline gear may not be retained at the surface, but can fall off the longline hooks before reaching the surface. Hence surface observations of some benthic bycatch are likely to underestimate of the actual level of interaction.

In May 2008, a randomised longline survey, consisting of 15 standardised sets over 2 strata covering areas of commercial fishing activity was conducted from aboard the Australian flagged longliner FV Janas BANZARE Bank within CCAMLR Statistical Division 58.4.3b. Catch rates were very low, ranging between 0 and 225 kg.1000 hooks-1, consistent with toothfish being depleted to low densities across the majority of the surveyed area. Catches of toothfish consisted of both species of Dissostichus, with D. mawsoni found across the entire survey area while D. eleginoides was mainly found on the shallow areas on the western part of the Bank. Data on size distribution and size at maturity indicate that the D. mawsoni population is almost entirely large mature fish with a bias towards males, which are shown to mature at a smaller size than females. As the population does not contain juvenile lifestages, we hypothesise that the fish encountered originate from nearby populations in east Antarctica where juveniles of both sexes are caught. The D. eleginoides population consisted of approximately equal proportion of males and females, and few mature individuals were detected. Contrasts in the population characteristics of the two species of Dissostichus indicate that species specific management should be considered for this area. Data on major bycatch species Macrourus carinatus and Raja taaf, including size distribution, sex ratio and size at maturity, are also presented.

A survey of mackerel icefish, Champsocephalus gunnari, was undertaken in Division 58.5.2 in the vicinity of Heard Island in July 2008 to provide the information for an assessment of short-term annual yield in the 2008/2009 CCAMLR season. This paper provides a preliminary assessment of yield for the area of Division 58.5.2 to the west of 79o 20’ E using standard CCAMLR methods. The strong year class detected in last year’s survey is now fully recruited as the 2+ cohort, and dominates the population.

Tagging of the three species of skates taken as by-catch in the Heard Island and McDonald Islands toothfish fishery, Bathyraja eatonii, B. irrasa and B. murrayi has taken place over the last eight years with nearly 6,000 skates tagged. The recapture rate has been low, less than one percent. Movement after tagging shows that these fish are recaptured only short distances from where they were released. The mean distance between release and recapture was 4.8 nautical miles, even though the majority had been at liberty for several years. In order to enhance the ease of identification of skates and to ensure good quality of the data, one page identification sheets were developed for each species which will be used by observers on board fishing vessels.