Summary: Fish were caught with nets and killed.

Procedure: Adult fish of different species were collected - two diadromous species (fish that migrate between salt and fresh water) and two lacustrine species (fish that live in lakes). From December 2019 to January 2020, a total of 64 fish were captured using either fyke nets or seine nets and transported to an indoor lab. Fish were killed with AQUI-S 20 E (a type of liquid anaesthetic) and dissected.

Purpose: To try and better understand the factors affecting how viruses spread in these fish species. Their role in the ecological community, their distribution across NZ, and their ability to live in both fresh and saltwater makes these fish attractive models for understanding how ecological factors and life-history traits may influence the structure and number of fish viruses.

Source: Journal article

Year published: 2022

Summary: Fish were either bought or caught and killed so that they could be dissected.

Procedure: Sixteen fish species were collected or provided by commercial fishers along the east coast of the South Island between 2017 and 2018. Deeper water species, such as lookdown dory orange roughy and Hoki, were acquired from the Chatham Rise trawl surveys. Caught fish had their head and body (length) measured. They were frozen and taken to a laboratory where tissue samples were taken.

Purpose: To assess how climate change affects marine food webs by comparing the distribution and presence of modern and historical fish communities and investigating the impacts of environmental changes (including those caused by humans). This is important to the global fisheries industry as it’s dependent on the existence of functioning marine food webs.

Source: Journal article

Year published: 2022

Summary: Normal and transgenic zebrafish were fed normally or way too much. The fish were taken out of the water for glucose tests and blood samples.

Procedure: Embryos of zebrafish were injected with genetic material to create a mutation. They were used for breeding more fish with this mutation that throws off their blood glucose regulation. From three months old, fish were either overfed or normally fed for six weeks. Body weights and lengths were measured regularly. At the end of the six weeks, Metformin (a diabetes medicine) was dissolved in the tank water and anaesthetized fish were then taken out of the water. Covered on soaked tissue paper, a needle was inserted into the dorsal aorta to take blood samples. For glucose immersion, fish were placed in tanks with 1% glucose in the water; Blood samples were taken daily. For glucose tolerance tests, fish weren't fed for 3 days. They were anaesthetised again and injected with glucose. More blood samples were taken for three hours so that their blood glucose levels could be measured.

Purpose: To try and learn about human adipostasis (formation of fat tissue). Glucose (a simple sugar) and leptin (a hormone) affect blood glucose levels, so they are investigated here.

Source: Journal article

Year published: 2022

Summary: Nine fish were caught by underwater spearing and killed so that samples could be collected from their digestion tracts.

Procedure: Three adult K. sydneyanus were caught and killed by underwater spearing from Little Barrier Island in the Hauraki Gulf in August 2008 so that the microbes in their guts could be measured. Another six adult K. sydneyanus were caught the same way from Nelson Island near Great Barrier Island in the Hauraki Gulf in May 2018. They were immediately “processed” (no details) and their guts were removed.

Purpose:
To research if the kind of microbes in fish guts influences the fermentation of their food. They picked Kyphosus sydneyanus, a marine herbivorous fish found in the warm temperate waters of Australia and New Zealand.

Source: Journal article

Year published: 2022

Summary: Sharks were caught and kept in outside tanks. For the experiments, they weren't fed for at least 4 days, of which they spent 3 days in a measuring chamber not much bigger than the shark. Oxygen consumption and behaviour were continuously recorded for the last 24 hours.

Procedure: Seven draughtsboard sharks (766–2,705 g in weight) were collected from Hauraki Gulf, north-eastern New Zealand and kept in outdoor tanks. They were fed pilchards for two weeks before the experiments. Before the measurements, they weren't fed for 3 days. Experiments were done in an acrylic measuring chamber (87cmx32cmx17cm; 38 litres) within a flow-through tank. For 24 hours, overhead video recordings were taken with infrared lighting. Measurements of their breathing were taken two days later to allow each animal to get used to the chamber.

Purpose: To try and better understand if sharks sleep to conserve energy. These researchers want to learn more about the evolution of sleep, and sharks are one of the earliest vertebrates with jaws.

Source: Journal article

Year published: 2022

Summary: Zebrafish larvae were injected with bacteria to test how their immune system responds. This was repeated to test how well the immune system reacted and how long the effect lasts.

Procedure: Larval zebrafish, who exclusively rely on the immunity their genetics provide (innate immunity), were treated with Salmonella bacteria. It was then tested if the immune system learned from the first injection to better protect the organism. For that, the larvae were infected again with either Salmonella or Streptococcus. Embryos were also injected with β-glucan, a well-known trigger of trained immunity, to observe if that would increase survival against similar bacterial infections. These results provide a foundation to exploit the experimental attributes of larval zebrafish to further understand this form of immunological memory. We have only the abstract available now, and we will provide more detail once available.

Purpose: To investigate learned immunity in zebrafish larvae. If their immune system has this ability, they will want to use these fish as an animal model for immunity studies.

Source: Journal article

Year published: 2022

Summary: Snappers were caught from the wild and bred. Around eighty-thousand of their offspring were hatched and raised. At regular “grading” events, injured and deformed fish were disposed of. At just under a year old, around twenty-two-thousand were left and transported to a sea pen, where they were raised to 17.5 months old before “harvesting”.

Procedure: The New Zealand Institute for Plant and Food Research Limited (PFR) started a snapper breeding program in Nelson in 2016. At the Nelson Research Centre, two batches of eggs collected from natural reproduction were hatched in 2015. Approximately 80,000 larvae were raised in 5,000-litre tanks. In May 2015, 54,000 fish were kept for growing; the rest was either used for “grading” or had died earlier. Every two to six weeks, fish were graded and injured or deformed fish were removed. At 180 days of age, 39,000 fish remained and were kept sorted by size. Final grading and removal of deformed and injured fish were performed in November 2015. A total of 21,891 fish were transported to a sea pen (at around 300 to 320 days old). After 17.5 months of on-growing (April 2017), snappers were “harvested”, and the visually 200 biggest and smallest were chosen for genome sequencing.

Purpose: To try and improve breeding for aquaculture and explain growth changes in wild populations. Being able to select breeding stock for a specific growth gene would speed up breeding successes and increase profits.

Source: Journal article

Year published: 2022

Summary: Fish in aquaculture were divided into groups and fed diets with different fat content. Fish were anaesthetised and faeces samples squeezed out of them.

Procedure: Fish (200g to 500g) were kept in tanks (5qm) at the Cawthron Aquaculture Park, Glenduan, Nelson. After 3 weeks of acclimatisation, all fish were weighed, measured, and put into nine tanks with 90 fish each in September 2017. Three feeding groups received diets with different fat contents (~22%, ~24%, ~27%). Faeces samples were taken 11 weeks after starting the trial in November 2017, 6 fish per tank). Sampled fish were anaesthetised with Aqui-S (a liquid anaesthetic you put directly into the water) and faeces samples were “gently” squeezed out.

Purpose: To investigate what bacteria are in the faeces of healthy salmon and what increasing fat in their food does to them. Understanding this means they will know how much fat they can feed for maximum growth without making the fish sick.

Source: Journal article

Year published: 2021

Summary: Wild fish were caught, measured and frozen to be analysed.

Procedure: Fish were collected from commercial fishing by New Zealand Ministry for Primary Industries from June to October 2019. The species, catch location, length and weight of each fish were recorded. Fish were frozen and shipped to the analytical laboratory. Fish species collected were 101 orange roughy, 120 ling, 20 smooth oreo, 20 black oreo, 10 barracouta and 10 gemfish.

Purpose: To investigate the mercury content of different fish species to make sure they are safe to eat.

Source: Journal article

Year published: 2020

Summary: Fish were exposed to chronic stress for four weeks, while 57 non-stressed animals were kept as a control. Signs of stress were noted. At the end of the experiment, all were chilled to death.  

Procedure: 121 wild zebrafish were divided into treatment and control groups. They were separately kept in tanks for two weeks and checked for injury or sickness signs and behaviour changes at each feeding time. Then, fish were exposed to an Unpredictable Chronic Stress protocol for four weeks. The six stressors imitated husbandry procedures or environmental challenges. These were: chasing with a net, crowding, high water temperature, low water temperature, low water level, and air exposure. Signs of stress were monitored. These were: Fish at the surface, rapid breathing/gaping, lethargy, circling/twirling, loss of equilibrium, rubbing on surfaces, colour change, weight loss, pop-eyes, distended abdomen, skeletal deformity, masses/swellings, haemorrhage/redness, gas bubbles, protruding scales, fin erosion or lesion, and skin ulceration. Then, all fish were killed by rapid chilling at 2°C and dissected.

Purpose: To test if the chromosomes of zebrafish react to chronic stress. If so, this could be used as a marker for animal welfare.

Source: Master’s thesis

Year published: 2020