There is good news. Our new research<\/a> has found increasing numbers of fish species and wider distributions around Heard and McDonald Islands. While it\u2019s difficult to pinpoint the exact drivers of these increases, we believe it\u2019s a combination of factors: the removal of illegal fishing, changes in fishing practices to reduce bycatch, a long-established marine reserve, and possibly climate-driven increases in ocean productivity. <\/p>\n Fish communities rebounding<\/p>\n The undulating terrain and nutrient-rich waters washing up from 4,000m deep onto the Kergeluen Plateau have helped make this area a hotspot for fish species. <\/p>\n Before Australia established an exclusion zone around the islands, the region was heavily targeted by international trawlers likely causing significant damage to many forms of life on the seafloor. <\/p>\n In the 1990s, illegal fishers using longlines targeted these waters for the high-value toothfish and large catches of species such as marbled rockcod. By the early 2000s, illegal, unreported and unregulated fishing was stamped out due to joint surveillance efforts by Australian and French authorities. France controls the Kergeluen Islands 450km away. The waters are now monitored by satellite. <\/p>\n Historically, authorised fishers also relied on trawling to catch toothfish. In 2003, the fishing industry began shifting to longline methods for catching toothfish which has likely benefited seafloor habitats, bycatch species and fish communities. Today, trawling efforts in the region are much reduced outside a small fishery for mackerel icefish. <\/p>\n The toothfish is sought after by top restaurants around the world and the area has a well-managed and lucrative toothfish and mackerel icefish fishery considered sustainable<\/a>. Only 2,120 tonnes can be taken a year under catch limits set by the Australian Fisheries Management Authority.<\/p>\n Patagonian toothfish are still caught in a sustainable way avoiding trawling. A no-take marine reserve was declared over some of the waters around Heard and McDonald Islands in 2002 and expanded in 2014. This is also likely to have contributed to the increase in fish communities. In January 2025, the Australian government significantly expanded the size of the reserve, including no-take, habitat protection and national park zones. This should further boost protection. <\/p>\n The region\u2019s remoteness, harsh conditions and ocean depth make it very difficult to study how fishing and climate change affect fish communities.<\/p>\n The data we used in our research comes from a long-term monitoring program<\/a> conducted by fishers and managed by the Australian government. Every year since the late 1990s, a fishing vessel undertakes a number of short trawls at different depths. The presence and abundance of different species is recorded. <\/p>\n We used contemporary statistical approaches to model the entire dataset, examining how all seabed fish species respond to factors such as water temperature, depth, climate and marine reserve status.<\/p>\n Our analysis of data from 2003\u201316 found that despite a warming ocean, bottom-dwelling fish numbers have broadly increased. This includes species more likely to be caught as bycatch in fishing nets, such as Eaton\u2019s skate<\/a>, grey rockcod and deep-water grenadier species. Strikingly, the number of species in a single sample more than doubled over a 13 year-time period. <\/p>\n Every year, a fishing vessel does a research trawl to get data on species abundance. What\u2019s next?<\/p>\n This area is a climate change hotspot. Major ocean currents such as the Polar Front are changing<\/a> and water temperatures are rising<\/a>. These changes are boosting production of phytoplankton, the microscopic floating plants that underpin food webs. We don\u2019t know yet if this is another reason fish distributions are changing, and we don\u2019t know what rising water temperatures will mean for polar-adapted fish species.<\/p>\n![\"two](\"https:\/\/www.newsbeep.com\/au\/wp-content\/uploads\/2025\/10\/file-20251027-56-rc2zjh.jpeg\")
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\n Henry Wilson\/AFMA, Author provided (no reuse)<\/p>\n![\"fishing](\"https:\/\/www.newsbeep.com\/au\/wp-content\/uploads\/2025\/10\/file-20251027-56-8cbkic.jpeg\")
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\n Henry Wilson\/AFMA, Author provided (no reuse)<\/p>\n