Algemeen

Steelhead stocks are rock-bottom in British Columbia

Steelhead anglers may have to start looking for another fish to catch. Four groups have released a joint statement sounding the alarm about the decline of steelhead numbers returning to B.C. rivers. The focal point of that concern is the Thompson River, a major tributary of the Fraser River. Where it once supported a thriving recreational steelhead fishery of 4,000 spawners in the mid-1980s, today the Thompson River has about 250 spawners projected for 2018.

Canadian fish stocks are at risk of collapse

Some fish stocks in Canada are at risk of collapse. Some estimates put the overall decline of marine populations at 50 per cent of levels in the 1970s, although the numbers vary depending on the species and its location. Oceana Canada, a scientific research and lobby group, just released its first audit of 159 separate marine fish stocks and found 26 in critical condition, 22 of those in Atlantic Canada.

Wild salmon populations in New Zealand show significant and alarming drops in numbers since about the mid-1990s

As wild salmon populations have declined dramatically, Fish and Game New Zealand (FGNZ) is hosting a symposium to discuss the problem. FGNZ councillor Matthew Hall, of Ashburton, said population surveys carried out every year, including in Otago rivers, had shown significant and alarming drops in numbers since about the mid-1990s. ''The New Zealand population of sea salmon in the last 10 years has been the lowest since they were introduced in the 1900s,'' Mr Hall said.

Negative impacts of neonicotinoids in aquatic environments are a reality

Initial assessments that considered these insecticides harmless to aquatic organisms may have led to a relaxation of monitoring efforts, resulting in the worldwide contamination of many aquatic ecosystems with neonicotinoids. The decline of many populations of invertebrates, due mostly to the widespread presence of waterborne residues and the extreme chronic toxicity of neonicotinoids, is affecting the structure and function of aquatic ecosystems. Consequently, vertebrates that depend on insects and other aquatic invertebrates as their sole or main food resource are being affected.

Infectieziektes die amfibieën op de rand van uitsterven brengen

Wereldwijd gaat het niet goed met amfibieën en infectieziektes zijn een zeer belangrijke factor die achteruitgang en uitsterven van soorten versnellen. Twee van de bekendste amfibieziektes zijn Chytridiomycose en Ranavirus. Beide komen ook in Nederland voor en zorgen lokaal voor de achteruitgang van populaties. Er zijn echter meer ziektes waar amfibieën mee te maken hebben, waaronder Amphibiocystidium-infecties. Amfibieën die zijn geïnfecteerd met soorten uit het genus Amphibiocystidium vertonen wittige tot doorzichtige blaasjes op de huid (<1 cm).

Populations of river herring have undergone a significant decline

The annual arrival of the river herring signifies the official arrival of spring. It draws many of us to the run, to witness the upward migration of these beloved fish, who after surviving several years at sea, return to spawn in the same exact lake or pond where they were born. River Herring [Alewife (Alosa pseudoharengus) and Blueback Herring (Alosa aestivalis)] are referred to as a “keystone species” as they are a vital part of the marine, estuarine, and freshwater food webs.

Once the pride of Kashmir, Wular Lake now struggles for survival

Fishing and other rural communities that have traditionally depended on Wular Lake are now struggling to earn a living from it, as shrinkage, siltation and ecological degradation take a toll on Kashmir’s largest flood basin. Wular, which was designated as a wetland of international importance under Ramsar Convention in 1990, is one of the largest freshwater lakes in Asia and the largest flood basin of Kashmir.

More than 15 southern waterways in New Zealand are on a list of rivers "lost or in noticeable decline" as public trout fisheries

More than 15 southern waterways appear on a list of rivers "lost or in noticeable decline" as public trout fisheries. The list was coordinated by NZ Federation of Freshwater Anglers executive member Steve Gerard. Southern waterways appearing on the list include the Pomahaka, Oreti, Makarewa, Mokoreta, Upukerora, Whitestone and Mararoa rivers, and the Waipahi, Otamita, Waimea, Lora, Otapiri, Dunsdale, Hedgehope, Titipua, Waimatuku, Orauea and Mimihau streams. Gerard said New Zealand's trout fisheries were "going downhill".

Researcher touts potential of frogs, toads in restoring native fisheries

Frogs, toads and salamanders often fall through the cracks of scientific study, but according to recently published research from Montana State University, they play a role so important they should be incorporated into strategies for conserving freshwater fisheries. In his first peer-reviewed paper as sole author, Niall Clancy, 22, said that native fish populations continue to decline around the world despite advances in management practices. Therefore, fisheries managers might want to add new approaches to the old.

Battle to save spotted handfish

The spotted handfish (Brachionichthys hirsutus), endemic to the Derwent River, is listed as critically endangered on the International Union for Conservation of Nature red list. It is also listed as endangered on the Tasmanian threatened species list. Handfish are coastal ­anglerfish that walk on the sea floor on their “hands”. There are 14 species distributed across South East Australia, with seven endemic to Tasmania and Bass Strait. Spotted handfish once extended up Tasmania’s East Coast as well as Frederick Henry Bay in the South East.