TY - JOUR
T1 - The invasive red seaweed, Dasysiphonia japonica, forms harmful algal blooms
T2 - Mortality in early life stage fish and bivalves and identification of putative toxins
AU - Young, Craig S.
AU - Lee, Cheng Shiuan
AU - Sylvers, Laine H.
AU - Venkatesan, Arjun K.
AU - Gobler, Christopher J.
N1 - Publisher Copyright:
© 2022
PY - 2022/10
Y1 - 2022/10
N2 - In recent decades, the rate of introduction of non-indigenous macroalgae has increased. While invasive seaweeds often outcompete native species for substrata, their direct effects on marine life are rarely described. Here, we describe ‘red water’ events caused by the decay of blooms of the invasive red seaweed, Dasysiphonia japonica, in Great South Bay, NY, USA, and the ability of water from such events to induce rapid and significant mortality in larval and juvenile fish (Menidia beryllina, Menidia menidia, and Cyprinodon variegatus) and larval bivalves (Mercenaria mercenaria and Crassostrea virginica). All species studied experienced significant (p<0.05) reductions in survival when exposed to macroalgae in a state of decay, seawater in which the alga was previously decayed, or both. Both bivalve species experienced 50–60% increases in mortality when exposed to decaying D. japonica for ∼ one week, despite normoxic conditions. Among fish, significant increases (40–80%) in mortality were observed after 24 h exposure to decayed D. japonica and one-week exposures caused, on average, 90% mortality in larval M. beryllina, 50% mortality in juvenile (∼3 cm) M. menidia, and 50% mortality in larval C. variegatus. All fish and bivalve mortality occurred under normoxic conditions (dissolved oxygen (DO) >7 mg L–1) and low ammonium levels (< 20 µM), with the exception of C. variegatus, which expired under conditions of decayed D. japonica coupled with reduced DO caused by the alga. Screening of water with decayed D. japonica using liquid chromatography-mass spectrometry revealed compounds with mass-to-charge ratios matching caulerpin, a known algal toxin that causes fish and shellfish mortality, and several other putative toxicants at elevated levels. Collectively, the high levels of mortality (50–90%) of larval and juvenile fish and bivalves exposed to decaying D. japonica under normoxic conditions coupled with the observation of ‘red water’ events in estuaries collectively indicate the red seaweed, D. japonica, can create harmful algal blooms (HABs).
AB - In recent decades, the rate of introduction of non-indigenous macroalgae has increased. While invasive seaweeds often outcompete native species for substrata, their direct effects on marine life are rarely described. Here, we describe ‘red water’ events caused by the decay of blooms of the invasive red seaweed, Dasysiphonia japonica, in Great South Bay, NY, USA, and the ability of water from such events to induce rapid and significant mortality in larval and juvenile fish (Menidia beryllina, Menidia menidia, and Cyprinodon variegatus) and larval bivalves (Mercenaria mercenaria and Crassostrea virginica). All species studied experienced significant (p<0.05) reductions in survival when exposed to macroalgae in a state of decay, seawater in which the alga was previously decayed, or both. Both bivalve species experienced 50–60% increases in mortality when exposed to decaying D. japonica for ∼ one week, despite normoxic conditions. Among fish, significant increases (40–80%) in mortality were observed after 24 h exposure to decayed D. japonica and one-week exposures caused, on average, 90% mortality in larval M. beryllina, 50% mortality in juvenile (∼3 cm) M. menidia, and 50% mortality in larval C. variegatus. All fish and bivalve mortality occurred under normoxic conditions (dissolved oxygen (DO) >7 mg L–1) and low ammonium levels (< 20 µM), with the exception of C. variegatus, which expired under conditions of decayed D. japonica coupled with reduced DO caused by the alga. Screening of water with decayed D. japonica using liquid chromatography-mass spectrometry revealed compounds with mass-to-charge ratios matching caulerpin, a known algal toxin that causes fish and shellfish mortality, and several other putative toxicants at elevated levels. Collectively, the high levels of mortality (50–90%) of larval and juvenile fish and bivalves exposed to decaying D. japonica under normoxic conditions coupled with the observation of ‘red water’ events in estuaries collectively indicate the red seaweed, D. japonica, can create harmful algal blooms (HABs).
KW - Allelopathy
KW - Bivalves
KW - Fish
KW - Invasive species
KW - Macroalgae
KW - Toxicity
UR - http://www.scopus.com/inward/record.url?scp=85135703795&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85135703795&partnerID=8YFLogxK
U2 - 10.1016/j.hal.2022.102294
DO - 10.1016/j.hal.2022.102294
M3 - Article
C2 - 36195420
AN - SCOPUS:85135703795
SN - 1568-9883
VL - 118
JO - Harmful Algae
JF - Harmful Algae
M1 - 102294
ER -