Bad matching between hatching and acidification: a pitfall for the burbot, Lota lota, off the river Kyrönjoki, Baltic Sea

Climatic effects on water quality in areas with acid sulfate soils with commensurable consequences on the reproduction of burbot (Lota lota L.)

“…The reoccurring recruitment failure without visible mass kills of fish found in this study is in line with Hudd and Kjellman ( 2002 ), who pointed out that it is not only the severity of acidification, but especially the timing of when the lowest pH occurs that has significance for the survival of a year class. Similar effects are also documented for other fish species, and frequently occurring poor recruitment may well have more devastating consequences to fish populations than mass kills of adult fish (Hudd 2000 ).…”

“…Similar effects are also documented for other fish species, and frequently occurring poor recruitment may well have more devastating consequences to fish populations than mass kills of adult fish (Hudd 2000). However, in contrast to this work, Hudd and Kjellman (2002) found the critical period for the survival of a year class to occur around the time of ice breakup and hatching which takes place commonly in April. The discrepancy between the reported critical periods deciding the reproduction success may be due to the warmer winters with rain instead of snow during the 2000s (Toivonen et al 2013), causing a shift in the timing of the acidic surges from spring toward winter.…”

“…The spawning and early life stages of fish are more sensitive to acidic events, causing frequent failure in offspring production with no immediate obvious effects. Instead, the effects appear as declining and abnormally fluctuating fish stocks and difficulties for fish stocks to recover between visible mass kills of fish (Böhling et al 1991 ; Hudd et al 1986 ; Hudd and Kjellman 2002 ; Kjellman et al 1994 ; Sammut et al 1995 ; Sayer et al 1993 ). Since fish of several species from large areas along the coast use estuaries for reproduction, the effects on fish populations are widespread (Sutela et al 2012 ).…”

Winter Disturbances and Riverine Fish in Temperate and Cold Regions

“…Susceptibility may also vary during winter as a function of ongoing ontogenic processes. For instance, mass kills of burbot larvae (Lota lota) in a Finnish river did not occur in years during which the soil-borne acidification peak was highest but only when it occasionally overlapped with the burbot's most vulnerable development stages-the hatching stage and the free-swimming larval stage (Hudd and Kjellman 2002). There is some empirical evidence of a negative synergism for fish in an impaired physical condition that experience winter disturbances.…”

Characterization of acid sulfate soils and assessing their impact on a humic boreal lake

“…The summers preceding these events were unusually dry, causing the groundwater level to drop to an exceptionally low level, increasing the oxidation of sulfides in the catchment. Moreover, newly hatched fish fry is more sensitive to acidic and metal rich water (Vuorinen et al, 1993), and it is plausible that mass kills of newly hatched fish fry occur frequently, and affect fish populations more severely than the relatively rare mass kills on adult fish (Hudd and Kjellman, 2002).…”