The only difference between the marine and the bovine formulas lies in the source of the collagen, being tilapia or beef. One formula is not recommended over the other, it's a matter of preference. The makers of Calorad introduced the marine formula more than six years ago to address a vegetarian and kosher market. The main difference in the alternate collagen sources is the actual composition of the amino acid chain (certain amino acids will be in higher or lower proportions).
We do not have any evidence to conclude that one formula works better than the other for weight loss, every body is different and again, it is a matter of preference.