To cite package ‘rfishbase’ in publications use:

  C. Boettiger, D. T. Lang and P. C. Wainwright. "rfishbase: exploring,
  manipulating and visualizing FishBase data from R". In: _Journal of
  Fish Biology_ 81.6 (Nov. 2012), pp. 2030-2039. DOI:
  10.1111/j.1095-8649.2012.03464.x

A BibTeX entry for LaTeX users is

  @Article{,
    title = {rfishbase: exploring, manipulating and visualizing {FishBase} data from R},
    author = {Carl Boettiger and Duncan {Temple Lang} and Peter Wainwright},
    month = {nov},
    year = {2012},
    publisher = {Wiley-Blackwell},
    journal = {Journal of Fish Biology},
    url = {https://doi.org/10.1111/j.1095-8649.2012.03464.x},
  }