New Zealand Aquatic Environment and Biodiversity Report No. 214. 168 p.
(Manuscript 3334)

A spatial risk assessment of threats was undertaken for Hector’s and Māui dolphins, to inform a revised Threat Management Plan (TMP) for the species. A Bayesian risk model was developed using the spatially-explicit fisheries risk assessment (SEFRA) approach, incorporating revised estimates of Hector’s and Māui dolphin spatial density and intrinsic population growth rate. The risk model was used to estimate spatial overlap, annual deaths and risk for commercial fisheries and lethal non-fishery threats, including toxoplasmosis. Spatial overlap was estimated for other threats.

New Zealand Aquatic Environment and Biodiversity Report No. 215. 18 p.

A Bayesian Māui dolphin population model was developed integrating information from genetic “mark-recapture” and population size estimates. Model runs incorporated estimates of historical annual deaths from commercial fisheries and toxoplasmosis obtained from a separate spatial risk assessment. These models were then used to simulate the effects of estimated threat-specific mortality rates on future population growth.

This study provides an assessment of the impact of fishing-related fatalities on the populations of 35
marine mammal (sub)species that inhabit New Zealand waters. The assessment included mortalities
caused by trawl, longline, set-net and purse-seine fisheries within New Zealand’s Exclusive Economic
Zone (EEZ). The risk assessment was an implementation of the Spatially Explicit Fisheries Risk Assessment
(SEFRA) method. Risk was defined as the ratio of Annual Potential Fatalities (APF; an estimate of
the number of marine mammals killed in fisheries each year) to the Population Sustainability Threshold
(PST; a measure of the population productivity). A risk index higher than one indicates that fisheries
mortalities are at a level that may prevent the population increasing to, or remaining above, half the
carrying capacity in the long term.

Limited information is available on the understanding and preferences of the young, old, pregnant, and immunocompromised consumers on food safety matters. As such the outcomes of this report will be used to inform NZFS risk management/risk communication activities i.e., the development and implementation of strategies/food safety messaging/campaigns used to engage with YOPI.

New Zealand’s Hector’s dolphins are an endangered species. A key threat to their survival is entanglement in fishing gear, including trawl nets. In this study, we report on a field trial where underwater microphones (hydrophones) were fitted to trawling equipment and the echolocation clicks naturally produced by Hector’s dolphins were localised to determine how the dolphins interacted with the trawling equipment as it moved through the water. The hydrophones were protected within custom-built cages to withstand the physical stress associated with being attached to fishing equipment that is dragged along the seabed. The field trial was conducted off the coast of Timaru, New Zealand, in September and October 2022. While the hydrophones recorded dolphin sound underwater, a Fisheries New Zealand observer on the boat also looked out for dolphins.

The protective cages around the hydrophones proved effective and we were able to successfully localise dolphins. Dolphins were localised moving towards the mouth of the fishing net from various approach angles, and, on several occasions, we were able to successfully distinguish multiple dolphins each moving along different paths. Even though we only analysed a subset of the acoustic data from each trawl, dolphin clicks were detected acoustically during trawls on more occasions than the observer on the fishing boat was able to see dolphins. Unfortunately silt from the seabed entered some of the connections between the hydrophones and the acoustic recorder, which resulted in corrupted data on some days, but overall the field trial was successful.

This study showed that listening for the presence of dolphins can be more effective than looking for dolphins from a boat. We suggest that a combination of listening and looking for dolphins would be the most effective way to detect dolphins that might be near the fishing net. In the long term, the listening system described here could be developed into a real-time warning system that alerts the fishing vessel master when dolphins are close to the fishing net. If the vessel master is aware of the dolphins, they could avoid activities that result in high-risk of entanglement, such as sharp turns or drawing in the net at the end of the trawl. Dolphin detection could also help with targeted use of devices that encourage the dolphins to move away from the high-risk areas—such devices emit noise and should be used as little as possible to minimise noise pollution and disturbance to the dolphins.

Collecting kaimoana from the sea is a much-loved tradition for many New Zealanders and their families. However, there are some risks you should be aware of before you head out to the coast.

This booklet provides information on the food safety risks associated with wild game and game birds to help hunters minimise risks and make safe decisions about the wild food they catch, store and eat.

The study investigates cryptic mortality (i.e., deaths that are not observed) of seabirds in New Zealand’s trawl fisheries, separately for net captures and warp cable strikes. For net capture-related mortality, the results suggest that, on average, mortality was 2.5 times higher than when only based on observed captures. For warp strikes, estimates varied based on data sources, highlighting the need for tailored data collection due to uncertainties and sparseness in the current dataset.

The Spatially Explicit Fisheries Risk Assessment framework has recently been updated and applied to assess the fisheries risk to seabird populations within the New Zealand EEZ. In the current report, the approach is applied to seabirds globally in the southern hemisphere. Catchabilities were estimated from New Zealand captures. Then global fishing effort and species distributions were collated and used to assess the risk to seabirds from predicted fisheries captures throughout their range.