Water quality – What about the fish and the anglers?

By Waiology 31/10/2013 5


By Neil Deans

Un-muddying the Waters : Waiology : Oct-Dec 2013New Zealand is blessed with an abundance and multitude of freshwaters which provide the habitat for an equally diverse array of species, including both native and introduced fish and wildlife. Some of these have intrinsic value; others are also valued because they provide food or recreational pursuit, or are indicators of a healthy environment.

Flyfishing
(Credit: G. Krewitt.)

Anglers and game bird hunters have had a statutory interest and involvement in what lives in our freshwaters for over 150 years since Acclimatisation Societies (from which Fish and Game NZ was formed in 1990) were first established. While their early emphasis was on transplanting species here from elsewhere the primary focus of anglers and hunters for over 50 years has been on the protection of the habitats where these animals reside.

Wetlands were appreciated by duck hunters long before these became of wider public interest in the 1980s. The former Auckland Acclimatisation Society, for example, began to buy swamplands (then deemed “wastelands”) in the lower Waikato River catchment in the 1940s. Auckland Waikato Fish & Game now owns more than 2500 ha, actively managed and conserved as wildlife habitat, saving it from being drained for agricultural land development.

The 150,000 Fish & Game-licensed anglers and hunters know that the quality of their recreational opportunities is directly related to the quality of the habitats in which their quarry resides, as well as the access to such areas.

_MG_1968
(Credit: G. Krewitt.)

Trout are amongst the most studied fish in the world, and are known to have relatively high water quality and quantity requirements. Trout in New Zealand can grow to amongst the largest in the world. This, combined with the scenic splendour of our river and lake catchments, attracts thousands of anglers annually from overseas. High quality habitats that grow large trout also equate to the public perception of high quality freshwaters; quite compatible with other instream interests like swimming or kayaking.

Successful anglers become attuned to the freshwater environment and ecosystem; they notice whether caddis or mayflies are hatching and being taken by trout and what flow or water conditions are most likely to entice trout to take lures. Because anglers go ‘off the beaten track’ in their pursuit of trout, they notice changes in the habitat and degradation which might otherwise go unnoticed.

It is no coincidence that anglers’ growing frustration with the inability/unwillingness of water managers to address declining freshwater habitats and unsustainable land uses causing this led to Fish & Game’s ‘Dirty Dairying’ campaign of the early 2000s. Although confrontational, this connected trout and their habitats via anglers to the general public’s increasing concern over the sustainability and inappropriateness of some intensive farming practices.

Though such campaigns successfully raised awareness of the issue, the worrying trend in recent years has been that the statutory water managers – the Department of Conservation, Ministry for the Environment and regional councils – are often still failing to address the causes of adverse impacts to freshwater habitats. Hard limits on the use of water and its assimilative capacity through regional plans are essential, providing certainty for both the public and for water users with their consents. Granting consents to use water has been easier than limiting its use through regional plans; often leading to over-allocation of water or its assimilative capacity to process contaminants.

The Land and Water Forum brought interested parties together in an attempt to reach a consensus on the way forward for managing this most precious resource, and it was agreed that setting and holding to limits in water use is crucial to sustainable management. The challenge now is to make this happen in all catchments.

As far as anglers and hunters are concerned, the test of whether we have achieved sustainable management is whether we have access to healthy and abundant stocks of fish and wildlife in our freshwaters. Anglers and hunters will keep watch to ensure that we can still enjoy and appreciate the high quality of our rivers, lakes and streams as a key point of difference between this country and most others.


Neil Deans is the Fish and Game Regional Manager for Nelson and Marlborough with part time national responsibility for freshwater resource management.


5 Responses to “Water quality – What about the fish and the anglers?”

  • Neil,

    Some of your comments seem out of date. And certainly your article is ignoring overall current understanding that water quality is improving. See the link below.

    http://www.mfe.govt.nz/environmental-reporting/fresh-water/river-condition-indicator/summary-key-findings.html

    I fish and regularly drink from one of the ‘dirtiest’ rivers out there. I wonder if we are ignoring the truth, that things are improving and not actually as bad as your article might suggest.

  • Neil, which water quality indicators are most relevant to angling conditions? Presumably not E. coli, but I assume MCI (being a measure of fish food) would be high. [DC]

  • Also, I am curious how water quality conditions are changing for rivers of relevance to anglers. Urban sites, which tend to show the greatest improvements, are not where I’d expect to find recreational fishers. [DC]

  • Thanks Mr E. You refer to the national data gathered by MfE, based largely on data on our larger rivers which are part of a national monitoring network admininistered by NIWA. This excludes any smaller rivers, which have had the most profound changes to their flows and water quality. These data are quite difficult to interpret over the country at large. There seems to have been an overall improvement (reduction) in ammonia levels in rivers, which is likely the result of improved standards or fewer point source discharges. There is, however, undoubtedly an increase in nitrate levels, which is acknowledged elsewhere on the MfE website, as follows:

    “There is a lot of variability, with rivers drawing water from predominately indigenous vegetated slopes having very high quality water. Rivers in the low-lands surrounded by pasture and in our cities are of poorer quality compared to those in indigenous land cover. Trends in urban rivers show that for the majority of sites, river water quality is improving. However, in some areas and for some nutrients, river water quality is decreasing, with pressure associated with land cover likely to be the drivers for these changes. ”

    This is the basis of my concern, and if anything, data from within regions on smaller rivers shows that the extent and number of smaller lowland streams which no longer meet standards for acceptable water quality to support aquatic life continues to increase; in other words that the situation continues to decline.

    As for which indicators are most important for trout in answer to DC; that is a difficult question for a simple answer. Clearly suitable oxygen and temperature ranges are crucial, as is sufficient water of suitable depth and water velocity in rivers, together with suitable food producing habitat to provide invertebrate food. Also the absence of toxic contaminants such as very high levels of nitrates or heavy metals, or elevated ammonia.

  • Nitrates.
    They’ve indicated about 21% improving 54% stable and 25% declining. Does this represent “undoubtedly an increase in nitrate levels”? I’m not so sure. There is little statistical information attached to the summary available.

    We need some context here. eg
    Ammonia SOE from MFE web site.
    http://www.mfe.govt.nz/environmental-reporting/fresh-water/river-condition-indicator/nutrient/index.html
    “Monitoring sites in catchments with predominately indigenous land cover had a median ammonia concentration of 0.005 mg/l. This is the limit that we can detect ammonia at most sites, so actual concentrations may be lower. The median concentration in pasture catchments is twice as high at 0.01 mg/l, and urban more than six times higher at 0.031 mg/l. The highest overall concentrations occur in a small proportion of monitoring sites within pasture catchments, indicating high variability. This is possibly due to the wide range of environments and land-use intensities associated with different farming types”

    The previous article has suggested 0.5ppm is need for fish death. I have read 0.26ppm is considered bad for fish. But I have read trout can get severe protozal infections at levels above 0.04ppm. All of these threshold levels are worse than SOE report indicates our average river will be. Even our worst rivers associated with the cities indicate we have little to worry about.

    In other words for ammonia, the average Joe fish has nothing to worry about.