Relationship between Habitat and Sport Fish Populations over a 20‐Year Period at West Lake Tohopekaliga, Florida

Abstract

Relationships between environmental variables and sport fish population parameters were investigated for West Lake Tohopekaliga from 1983 to 2002. Through time, the lake has undergone a process of cultural oligotrophication as indicated by reductions in nutrient and chlorophyll‐a concentrations because of improvements in wastewater treatment and the establishment of hydrilla Hydrilla verticillata in the system. With this decline in trophic state, angler catch and catch rate increased for largemouth bass Micropterus salmoides, but harvest and harvest rate decreased for black crappie Pomoxis nigromaculatus. Furthermore, the angler base of the lake shifted almost exclusively to those fishing for largemouth bass. Although angling effort for largemouth bass has increased through time with reductions in trophic state, angling effort for black crappies and sunfish species Lepomis spp. has declined. The growth of largemouth bass less than age 5 has also declined since the late 1980s, and the proportion of memorable‐sized fish in electrofishing catches decreased with decreases in total phosphorus. Areal coverage of hydrilla varied dramatically throughout this 20‐year period, and angler catch rate of largemouth bass as well as angler harvest rate of black crappies were positively correlated with hydrilla coverage. We believe the current level of nutrients and intermediate levels of vegetation (20–40%) should be maintained to balance the needs of both the angling and nonangling communities and to maximize the economic potential of the lake.

Effects of hurricane-induced hydrilla reduction on the largemouth bass fishery at two central Florida lakes

“…Angler creel estimates including effort, catch, and success have been positively correlated with SAV coverage , Wrenn et al 1996, Bonvechio and Bonvechio 2006. At Lake Okeechobee, Florida, hydrilla is considered one of the most important aquatic macrophytes because of its benefit to the recreational fishery for largemouth bass (Furse and Fox 1994).…”

“…The nonnative macrophyte hydrilla (Hydrilla verticillata) is frequently the dominant submersed plant in Florida lakes (Tate et al 2003, Bonvechio andBonvechio 2006) and in southeastern reservoirs (Slipke et al 1998, Kirk andHenderson 2006) and is present in systems throughout much of the United States (Michel et al 2004). Hydrilla provides a complex habitat type that supports a high density and biomass of prey items, provides cover, and reduces predation on age-0 largemouth bass.…”

Life cycle assessment of nutrient remediation and bioenergy production potential from the harvest of hydrilla (Hydrilla verticillata)

“…Although there is a growing consensus that moderate coverage (20e40%) of hydrilla provides excellent habitat for most fish and wildlife (Bonvechio and Bonvechio, 2006), past studies about the direct effects of aquatic plant harvesting on fish populations have found disparate results. On the one hand, Haller et al (1980) found significant by-catch removal of valuable sports fish during hydrilla harvests in Orange Lake, FL.…”

“…Given growing concerns with harmful algal blooms (e.g., Heisler et al, 2008) and the ongoing implementation of nutrient mitigation programs for many watersheds (e.g., Haire et al, 2007), there is a clear impetus for development of hydrilla control techniques that are more sensitive to the issue of nutrient liberation (Gu, 2006). Finally, some ecological research indicates that moderate levels of hydrilla coverage can have high habitat value for many native fish and wildlife species (Schramm and Jirka, 1989;Esler, 1990;Bonvechio and Bonvechio, 2006). One long-term research study in the Chesapeake watershed found that habitat benefits from hydrilla may be especially pronounced for ecosystems that are in a "recovery" phase following removal of nutrient burdens associated with cultural eutrophication (Rybicki and Landwehr, 2007).…”

“…Taken together, these issues have recently led some researchers and managers to suggest that alternatives to chemical treatment should be more widely considered, particularly in those systems where hydrilla coverage is already widespread and eradication is not feasible (Bonvechio and Bonvechio, 2006;Gu, 2006;Jones and Beardall, 2009;Hoyer et al, 2008). One of the primary alternatives for managing overgrowth of hydrilla and other aquatic plants is use of harvester machines to remove excess biomass from the water body.…”