Status and Trends of the Lake Ontario Macrobenthos

Abstract

Nalepa, T. F. 1991. Status and trends of the take Ontario macrsbenthos. Can. I. Fish. Aqe~at. Sei. 48: 1558- 1567.The benthic macroinvertebrate community sf Lake Ontario was examined relative to communities found in the other Great Lakes and also relative to trends over time. In the nearshore, populations are heavily influenced by municipal and industrial inputs. For example, oligochaete abundances in the nearshore are higher than in any of the other Great Lakes (excluding shallow Lake Erie), communities have been altered even to relatively deep depths near the major river mouths, and the pollution-sensitive Poritcsporeia hsyi is scarce along the southern shoreline east of the Niagara River mouth. In the profundal, benthic composition is similar to that Bound in the other Great Lakes, but biomass is less than might be expected given the amount of organic material settling to the bottom. Benthic standing stocks in this region have apparently declined almost threefold since the 1960s. Reasons for this decline do not appear to be related to trends in water column productivity or to predation pressure, but may be related to the accumulation of contaminants. Research needs include studies to assess benthic trends over a much broader area of the lake and studies to examine the impact sf sublethal levels of contaminants.La communaut6 des rnacrsinvert6br6s benthiques du lac Ontario a et6 comparee a d'autres communaut6s des Grands Lacs et son 6volution a 6t6 examinee. Pres des rives, les populations anirnales sont gravement affectees par les dechets rnunicipaux et industriels. Par exeppie, les oligochPtes sont plus abondants dans le lac Ontario que dans tous O e s autres Grands Lacs (sad le lac Erie, lequel est peu profond) pr&s des rives; les cornmunaut6s cant subi des changements meme dans O e s eaux relativement profondes pr$s de l'ernbouch~rre des principales riviPres et; Pontoporeia hoyi, organisme sensible 3 la pollution, est rare le long de la rive sud i l'est le lrembsuchure de la riviPre Niagara. Bans les profondeurs, la compssition du benthos est semblable 2 eelle des autres Grands Lacs, mais la biomasse est inferieure 21 ee qu'on pourrait s'attendre vu la quantite importante de matiPre organique deposant au fond. Les stocks d'organisrnes benthiques de cette region sont apparemiment presque trois fois rnsins importants que dans les annees 1960. II ne sernble pas que ce d6clin soit attribuable A une chute de la prsductivite biologique du lac su a une predation accrue : il serait plut8t reli6 21 I'accumulation des csntaminants. Les recherches futures devront tenter d'evaluer I'evolution du benthos en couvrant une portion du lac beaucoup plus importante et, par ailleurs, examiner I'irnpact de doses sublkthales de contaminants.A s a result of numerous field investigations over the past few decades, our knowledge of the benthic community in Lake Ontario is perhaps the most extensive of any of the Great Lakes. Surveys over the entire lake (Hiltunen 1969; Kinney 1 972; Nalepa and Thomas 1976; Golfni 1979) and more limi...

Reversal of eutrophication in Lake Geneva: evidence from the oligochaete communities

“…Furthermore, changes recorded in oUgochaete communities between 1982 and 1991 were the same as those attributed to a decrease of organic sedimentation (Lang, 1989b). However, the scardty of Peloscolex velutinus and Bythonomus lemani at a depth of 150 m (Lang, 1991), could indicate toxic effects in Lake Geneva as in Lake Ontario (Nalepa, 1991).…”

Diet effects on lipid composition, somatic growth potential, and survival of the benthic amphipod Diporeia spp.

“…(hereafter Diporeia). Nalepa (1991) calculated that Diporeia was the dominant benthic invertebrate in profundal habitats of the Lakes Superior, Michigan, and Ontario, accounting for 69-91% of total benthic biomass. In recent years, however, Diporeia biomass has declined (by 90% in some areas) in Lake Michigan (Nalepa et al, , 2009, and similar population declines have been observed in Lakes Ontario (Dermott and Kerec, 1997;Lozano et al, 2003), Erie (Dermott, 2001), and Huron (Nalepa et al, 2003).…”

Forestry Best Management Practices Relationships with Aquatic and Riparian Fauna: A Review

“…Sub-lethal effects of elevated sediment potentially include reduced immunity to disease, depressed growth rates, and impaired feeding and reproduction [22,23,[25][26][27][28][29][30][31][32][33].…”