Details

Autor(en) / Beteiligte

• STALLSMITH, BRUCE
• EBERSOLE, JOHN
• HAGAR, WILLIAM

Titel

The effects of acid episodes on Lepomis sunfish recruitment and growth in two ponds in Massachusetts, U.S.A

Ist Teil von

• Freshwater biology, 1996-12, Vol.36 (3), p.731-744

Ort / Verlag

Oxford BSL: Blackwell Science Ltd

Erscheinungsjahr

1996

Quelle

Wiley Online Library Journals Frontfile Complete

Beschreibungen/Notizen

• 1. The effects of transient acidity on the recruitment of Lepomis sunfish were examined in two ponds in Plymouth County, Massachusetts with on‐site monitoring systems. One pond had low buffering capacity and was sensitive to acidification and acid spikes, the other had better buffering with no acid spikes. Pond pH was continuously monitored over 3 years. 2. Young‐of‐the‐year (YOY) sunfish were collected and through otolith analysis aged in days since larval metamorphosis. Day‐classes were constructed from these age data. The YOY swim‐up day‐class distribution was more irregular with pronounced gaps in Maquan Pond than in the better‐buffered Furnace Pond. 3. The poorly buffered pond, Maquan, experienced irregular acid spikes, defined as a sudden lowering of pond pH from about 6.6 to below 5.3 for an hour or more. These spikes were associated with rainfall (P < 0.005). Acid spikes were not found at Furnace Pond. 4. The occurrence of acid spikes and diminished day‐classes from expected swim‐up values were significantly associated, based on pooled data from 3 years at Maquan Pond. 5. Transient acid spikes at Maquan Pond appear to harm Lepomis YOY at the vulnerable stage of metamorphosis, when their gills become fully functional and exposed to the environment. 6. Growth rates of Lepomis YOY were also studied. Length–age and weight–length growth relationships were examined for differences in instantaneous growth coefficients between years and between ponds. Length–age instantaneous growth coefficients ranged from 0.0114 to 0.0176 over five pond‐years. The slowest growth rates were in a warm, dry spawning season with the earliest average metamorphosis date.