Warmwater Fisheries Surveys of the I-82 Ponds (Yakima County) 2000 & 2001

The I-82 Ponds, Yakima County, Washington, were surveyed during May 2000 and September 2001. Past fisheries management and accessibility influenced survey and gear type selection for the ponds. As I-82 Ponds 1, 2, 3, 5, and 7 share a history of primarily warmwater fish populations and management, standard boat electrofishing, gill netting, and fyke netting surveys were conducted at each of these sites. Alternatively, I-82 Ponds 4 and 6, managed primarily for channel catfish and catchable trout, were sampled with boat electrofishing, trotlines, and slattraps to reduce channel catfish mortality associated with gill net sampling. Four of the I-82 Ponds (1, 2, 3, and 5) were sampled in May 2000; I-82 Pond 7 was sampled in September 2001 because high water prevented access to the pond in May 2000; and I-82 Ponds 4 and 6 were sampled in September 2001 using alternative methods. The primary objectives of these surveys were to describe the status of fish populations in each pond, to test the feasibility of sampling stocked channel catfish using trotlines and slat-traps, and to make recommendations on the future management at each pond.

• The I-82 Pond 1 fish community generally consisted of a low density largemouth bass population, a walleye population exhibiting characteristics of a population lacking an adequate prey base, and low density yellow perch and pumpkinseed sunfish populations. This is in sharp contrast to fish community assessments conducted pre- and post-walleye stocking in the early 1990s, which showed stunted populations of yellow perch and pumpkinseed sunfish. Management considerations for Pond 1 include: maintaining the outlet screen, installing a fishing dock, lifting the no harvest regulation for walleye, and stocking additional panfish.

• The I-82 Pond 2 fish community was found to be prey crowded with yellow perch and pumpkinseed sunfish. Largemouth bass density was low and fish sampled exhibited high condition. Management considerations include: increasing largemouth bass density, designing and installing a barrier to fish passage, and installing a fishing dock to enhance angling opportunity.

• I-82 Pond 3 was dominated by non-game fish undesirable to anglers and low density gamefish populations. Largemouth bass and panfish populations exhibited above average growth and condition. Largescale sucker and chiselmouth were abundant. Management considerations include: constructing a barrier to fish passage, increasing predator density, and chemical or mechanical removal of undesirable species.

• In I-82 Pond 5 largemouth bass exhibited characteristics of a balanced population; however, panfish population indices exhibited characteristics of overabundance likely due to interspecific competition. Channel catfish stocking provides some angling opportunity for large fish. Largescale sucker were a large proportion of the sample by weight. Managers should consider it a high priority to build and maintain an outlet barrier to fish passage, reduce the abundance of non-game species, and increase predator densities.

• I-82 Pond 7 was prey crowded with abundant bluegill and pumpkinseed sunfish and few predators. Largemouth bass were low in abundance and high in condition. Managers should consider whole or partial rehabilitation with chemical or mechanical methods and increasing predator abundance by stocking adult largemouth bass and channel catfish.

• Sampling with trotlines for channel catfish in I-82 Ponds 4 and 6 was effective for sampling adult fish. Although sample size was small, no mortality of fish sampled was observed. Slat-traps were not affective at either site. Channel catfish in several size groups were sampled at both ponds indicating successful stocking over several years. Managers should continue stocking channel catfish at the current level.