Algemeen

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.

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.

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.

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".

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.

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.

The tea houses in a fishing town in northern Istanbul were crowded with Turkish fishermen in the mornings in September, when they usually should have been busy on the sea as the fishing season just began. To the fishermen in Rumeli Kavagi at the northern mouth of Istanbul's Bosphorus Strait linking the Marmara Sea and the Black Sea, their disappointment resulted from the sharp decline in fish stocks. Fishing is the sole source of income for most residents in the town, which has been a major supplier of fish to Istanbul and other cities in the region.

Fishermen are concerned with the decline in trout numbers in the Tukituki, Ngaruroro and Tutaekuri rivers, with drought, winter floods, low water flows and agricultural pollution no doubt contributing factors. A survey in the past season showed that 68 per cent of fish caught in the Tukituki were adult fish, and only 32 per cent were juveniles. The results from recent national fly-fishing competitions saw a drop from 700 fish caught to only 36 in the last three years. This is a very disturbing trend.