An acoustic biomass survey of spawning orange roughy was undertaken on aggregations at Morgue and Graveyard hills in ORH 3B North-West Chatham Rise and at Rekohu, Spawn Plume and Mt Muck in ORH 3B East & South Chatham Rise, during June and July 2022 aboard FV San Waitaki.
Acoustic data were recorded using the vessel’s hull-mounted Simrad 38 kHz echosounder system and a dual-frequency (38 kHz & 120 kHz) Acoustic Optic System (AOS) deployed on the headrope of a trawl net.
In NWCR, spawning biomass at Morgue, a protected area, showed an increase over survey estimates in 2013, 2016 and 2021, while spawning biomass at Graveyard was considerably reduced compared to the previous survey estimate in 2013. In ESCR, spawning biomass at Rekohu in 2022 was lower than in 2013 and 2016, while at Spawn Plume the biomass was similar to that found in 2013 and 2016. At Mt Muck the biomass in 2022 was higher than the estimates in 2013 and 2016.
New Zealand has developed a spatially explicit risk assessment framework to assess the impact of fishing on protected species. It has been applied to a variety of charismatic fauna that are potentially vulnerable to the effects of fishing, including sea lions, seabirds and dolphins. In the case of seabirds, many of the species caught incidentally by New Zealand vessels are also caught outside of the Exclusive Economic Zone by high seas fisheries, particularly surface longliners fishing for tuna at high latitudes. This has led the risk assessment framework to be developed in a manner that can include global fishing effort and using global species distribution maps.
The Commission for the Conservation of Southern Bluefin Tuna (CCSBT) is the regional fisheries management organisation responsible for managing southern bluefin tuna surface longline fisheries. New Zealand has a history of collaboration with the CCSBT to develop a risk assessment for seabirds in the southern hemisphere. The current project is the most recent update to that work. This report provides a review and update of the biological input data used for the risk assessment, as well as a brief outline of the fisheries data. The assessment results were presented at the Fifteenth Session of the Working Group on Ecologically Related Species in June 2024. Model outputs and results are provided in the CCSBT report from that meeting.
Tangata Whenua of Tutukaka, Ngunguru and Hora Hora seek to protect and enhance ecosystem health in their rohe. In February 2024, the Rehuotane Ki Tai 186a temporary closure was established within three nautical miles of the coast. The harvest for rock lobster, cockle, crab, garfish, mussel, octopus, pāua, pipi, rock oyster, sea cucumber, sea horse, sea snail, starfish and tuatua was prohibited and no fishing with nets was allowed in Tutukaka Harbour or the Ngunguru and Hora Hora estuaries.
The Whāngai Mokopuna Rohe Moana management group initiated this research project in conjunction with appointed Tangata Kaitiaki to identify areas of healthy kelp forest and the extent of kina barrens and to trial kina removals at two sites. A cost effective and repeatable “rapid assessment” survey method was developed using readily available mapping software and in-water observations.
A simple habitat classification system was used by two experienced freedivers who reported what they saw to the crew on the support boat. We surveyed 17 km of coastline in three days, recording the location of each observation. There were extensive mature or active kina barrens observed in water depths of 10 metres or less. These areas had low biodiversity and few reef fish.
Two areas were selected for clearance of kina using free divers. Most kina collected in August and during follow up clearance in November had edible roe. Most kina were culled in situ because dive time was limited and kina density was high but some kina were harvested and distributed to hapū members. The project demonstrated the effectiveness of the rapid assessment method and provided valuable insights for future community led surveys and restoration initiatives.
New Zealand has developed a spatially explicit risk assessment framework to assess the impact of fishing on protected species. It has been applied to a variety of charismatic fauna that are potentially vulnerable to the effects of fishing, including sea lions, seabirds and dolphins. In the case of seabirds, many of the species caught incidentally by New Zealand vessels are also caught outside of the Exclusive Economic Zone by high seas fisheries, particularly surface longliners fishing for tuna at high latitudes. This has led the risk assessment framework to be developed in a manner that can include global fishing effort and using global species distribution maps.
The Commission for the Conservation of Southern Bluefin Tuna (CCSBT) is the regional fisheries management organisation responsible for managing southern bluefin tuna surface longline fisheries. New Zealand has a history of collaboration with the CCSBT to develop a risk assessment for seabirds in the southern hemisphere. The current project is the most recent update to that work. This report outlines details of the method used for work that was presented at the Fifteenth Session of the Working Group on Ecologically Related Species in June 2024. Model outputs and results are provided in the CCSBT report from that meeting.